libmicrohttpd2

microhttpd2_preamble.h.in (139464B)

---

 /* SPDX-License-Identifier: LGPL-2.1-or-later OR (GPL-2.0-or-later WITH eCos-exception-2.0) */
 /*
   This file is part of GNU libmicrohttpd.
   Copyright (C) 2006-2025 Christian Grothoff, Karlson2k (Evgeny Grin)
   (and other contributing authors)
 
   GNU libmicrohttpd is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.
 
   GNU libmicrohttpd is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.
 
   Alternatively, you can redistribute GNU libmicrohttpd and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2 of
   the License, or (at your option) any later version, together
   with the eCos exception, as follows:
 
     As a special exception, if other files instantiate templates or
     use macros or inline functions from this file, or you compile this
     file and link it with other works to produce a work based on this
     file, this file does not by itself cause the resulting work to be
     covered by the GNU General Public License. However the source code
     for this file must still be made available in accordance with
     section (3) of the GNU General Public License v2.
 
     This exception does not invalidate any other reasons why a work
     based on this file might be covered by the GNU General Public
     License.
 
   You should have received copies of the GNU Lesser General Public
   License and the GNU General Public License along with this library;
   if not, see <https://www.gnu.org/licenses/>.
 */
 
 /*
   Main goals for the libmicrohttpd 2.0 API:
 
   - simplify application callbacks by splitting header/upload/post
     functionality currently provided by calling the same
     MHD_AccessHandlerCallback 3+ times into separate callbacks.
   - keep the API very simple for simple requests, but allow
     more complex logic to be incrementally introduced
     (via new struct MHD_Action construction)
   - avoid repeated scans for URL matches via the new
     struct MHD_Action construction
   - better types, in particular avoid varargs for options
   - make it harder to pass inconsistent options
   - combine options and flags into more uniform API (at least
     exterally!)
   - simplify API use by using sane defaults (benefiting from
     breaking backwards compatibility) and making all options
     really optional, and where applicable avoid having options
     where the default works if nothing is specified
   - simplify API by moving rarely used http_version into
     MHD_request_get_info_fixed()
   - avoid 'int' for MHD_YES/MHD_NO by introducing `enum MHD_Bool`
   - improve terminology by eliminating confusion between
     'request' and 'connection'; add 'session' for HTTP2/3;
     use clear separation between connection and request. Do not mix the kind
     data in the callbacks.  Currently we are mixing things in
     MHD_AccessHandlerCallback and MHD_RequestCompletedCallback. Instead of
     pointers to struct MHD_Connection we should use pointers to (new) struct
     MHD_Request.
   - prepare API for having multiple TLS backends
   - use more consistent prefixes for related functions
     by using MHD_subject_verb_object naming convention, also
     at the same time avoid symbol conflict with legacy names
     (so we can have one binary implementing old and new
     library API at the same time via compatibility layer).
   - make it impossible to queue a response at the wrong time
   - make it impossible to suspend a connection/request at the
     wrong time (improves thread-safety)
   - make it clear which response status codes are "properly"
     supported (include the descriptive string) by using an enum;
   - simplify API for common-case of one-shot responses by
     eliminating need for destroy response in most cases;
   - avoid fixed types, like uint32_t. They may not exist on some
     platforms. Instead use uint_fast32_t.
     It is also better for future-proof.
   - check portability for embedded platforms. Some of them support
     64 bits, but 'int' could be just 16 bits resulting of silently
     dropping enum values higher than 65535.
     => in general, more functions, fewer enums for setup
   - Avoid returning pointers to internal members. It is not thread-safe and
     even in single thread the value could change over the time. Prefer pointers to
     app-allocated memory with the size, like MHD_daemon_get_static_info(enum
     MHD_enum_name info_type, void *buf, size_t buf_size).
     => Except in cases where zero-copy matters.
   - Use separate app calls/functions for data the will not change for the
     lifetime of the object and dynamic data. The only difference should be the
     name. Like MHD_daemon_get_static_info(enum MHD_enum_name info_type, void *buf,
     size_t buf_size) MHD_daemon_get_dynamic_info(enum MHD_enum_name info_type,
     void *buf, size_t buf_size) Examples of static data: listen socket, number of
     workers, daemon flags.  Examples of dynamic data: number of connections,
     quiesce status.  It should give a clear idea whether the data could be changed
     over the time (could be not obvious for some data) and thus may change the
     approach how to use the data in app.  The same for: library, daemon,
     connection, request. Not sure that dynamic data makes sense for the library.
   - Define response code in response object. There are a very little
     chance that response body designed for 404 or 403 codes will be used with
     200 code. However, the responses body for 307 and 308 could be the same. So:
     Add default response code in response object.
   - Make responses unmodifiable after first use. It is not thread-safe.
     MHD-generated headers (Date, Connection/Keep-Alive) are again
     part of the *request* and do not count as part of the "response" here.
   - Remove "footers" from responses. With unmodifiable responses everything should
     be "headers". Add footers to *requests* instead.
   - Add API for adding request-specific response headers and footers. To
     simplify the things it should just copy the strings (to avoid dealing with
     complicated deinit of possible dynamic strings).  After this change it should
     be possible to simplify DAuth handling as response could be reused (currently
     403 responses are modified for each reply).
   - Control response behaviour mainly by response flags, not by additional
     headers (like MHD_RF_FORCE_CLOSE instead of "Connection: close").
     It is easier&faster for both: app and MHD.
   - Move response codes from MHD_HTTP_xxx namespace to MHD_HTTP_CODE_xxx
     namespace. It already may clash with other HTTP values.
   - Postprocessor is unusable night-mare when doing "stream processing"
     for tiny values where the application basically has to copy together
     the stream back into a single compact heap value, just making the
     parsing highly more complicated (see examples in Challenger)
   - non-stream processing variant for request bodies, give apps a
     way to request the full body in one buffer; give apps a way
     to request a 'large new allocation' for such buffers; give apps
     a way to specify a global quota for large allocations to ensure
     memory usage has a hard bound
 
   - Internals: carefully check where locking is really required. Probably
     separate locks. Check out-of-thread value reading. Currently code assumes
     atomic reading of values used in other threads, which mostly true on x86,
     but not OK on other arches. Probably use read/write locking to minimize
     the threads interference.
   - Internals: figure out how to do portable variant of cork/uncork
   - Internals: remove request data from memory pool when response is queued
     (IF no callbacks and thus data cannot be used anymore, or IF
      application permits explicitly per daemon) to get more space
     for building response;
   - Internals: Fix TCP FIN graceful closure issue for upgraded
     connections (API implications?)
 
 */
 
 #ifndef MICROHTTPD2_H
 #define MICROHTTPD2_H
 
 #ifndef __cplusplus
 #  define MHD_C_DECLRATIONS_START_HERE_   /* Empty */
 #  define MHD_C_DECLRATIONS_FINISH_HERE_  /* Empty */
 #else  /* __cplusplus */
 /* *INDENT-OFF* */
 #  define MHD_C_DECLRATIONS_START_HERE_   extern "C" {
 #  define MHD_C_DECLRATIONS_FINISH_HERE_  }
 /* *INDENT-ON* */
 #endif /* __cplusplus */
 
 MHD_C_DECLRATIONS_START_HERE_
 
 /**
  * Current version of the library in packed BCD form.
  * (For example, version 1.9.30-1 would be 0x01093001)
  */
 #define MHD_VERSION 0x01990001
 
 #include "microhttpd2_portability.h"
 
 /* If generic headers do not work on your platform, include headers that
    define 'va_list', 'size_t', 'uint_least16_t', 'uint_fast32_t',
    'uint_fast64_t', and 'struct sockaddr', and then
    add "#define MHD_HAVE_SYS_HEADERS_INCLUDED" before including "microhttpd2.h".
    When 'MHD_HAVE_SYS_HEADERS_INCLUDED' is defined, the following "standard"
    includes will not be used (which might be a good idea, especially on
    platforms where they do not exist).
    */
 #ifndef MHD_HAVE_SYS_HEADERS_INCLUDED
 #  include <stdarg.h>
 #  ifndef MHD_SYS_BASE_TYPES_H
 /* Headers for uint_fastXX_t, size_t */
 #    include <stdint.h>
 #    include <stddef.h>
 #    include <sys/types.h> /* This header is actually optional */
 #  endif
 #  ifndef MHD_SYS_SOCKET_TYPES_H
 /* Headers for 'struct sockaddr' */
 #    if ! defined(_WIN32) || defined(__CYGWIN__)
 #      include <sys/socket.h>
 #    else
 /* Prevent conflict of <winsock.h> and <winsock2.h> */
 #      if ! defined(_WINSOCK2API_) && ! defined(_WINSOCKAPI_)
 #        ifndef WIN32_LEAN_AND_MEAN
 /* Do not use unneeded parts of W32 headers. */
 #          define WIN32_LEAN_AND_MEAN 1
 #        endif /* !WIN32_LEAN_AND_MEAN */
 #        include <winsock2.h>
 #      endif
 #    endif
 #  endif
 #endif
 
 #ifndef MHD_BOOL_DEFINED
 
 /**
  * Representation of 'bool' in the public API as stdbool.h may not
  * always be available and presence of 'bool' keyword may depend on
  * used C version.
  * It is always safe to cast 'MHD_Bool' variable to 'bool' and vice versa.
  * Note: it may be UNSAFE to cast pointers 'MHD_Bool*' to 'bool*' and
  *       vice versa.
  */
 enum MHD_Bool
 {
 
   /**
    * MHD-internal return code for "NO".
    */
   MHD_NO = 0
   ,
   /**
    * MHD-internal return code for "YES".  All non-zero values
    * will be interpreted as "YES", but MHD will only ever
    * return #MHD_YES or #MHD_NO.
    */
   MHD_YES = 1
 };
 
 
 #define MHD_BOOL_DEFINED 1
 #endif /* ! MHD_BOOL_DEFINED */
 
 #ifndef MHD_STRINGS_DEFINED
 
 
 /**
  * String with length data.
  * This type should always have valid @a cstr pointer.
  */
 struct MHD_String
 {
   /**
    * Number of characters in @e str, not counting 0-termination.
    */
   size_t len;
 
   /**
    * 0-terminated C-string.
    * Must not be NULL.
    */
   const char *cstr;
 };
 
 /**
  * String with length data.
  * This type of data may have NULL as the @a cstr pointer.
  */
 struct MHD_StringNullable
 {
   /**
    * Number of characters in @e cstr, not counting 0-termination.
    * If @a cstr is NULL, it must be zero.
    */
   size_t len;
 
   /**
    * 0-terminated C-string.
    * In some cases it could be NULL.
    */
   const char *cstr;
 };
 
 #define MHD_STRINGS_DEFINED 1
 #endif /* ! MHD_STRINGS_DEFINED */
 
 
 #ifndef MHD_INVALID_SOCKET
 #  if ! defined(_WIN32) || defined(_SYS_TYPES_FD_SET)
 #    define MHD_SOCKETS_KIND_POSIX 1
 /**
  * MHD_Socket is a type for socket FDs
  */
 typedef int MHD_Socket;
 #    define MHD_INVALID_SOCKET (-1)
 #  else /* !defined(_WIN32) || defined(_SYS_TYPES_FD_SET) */
 #    define MHD_SOCKETS_KIND_WINSOCK 1
 /**
  * MHD_Socket is a type for socket FDs
  */
 typedef SOCKET MHD_Socket;
 #    define MHD_INVALID_SOCKET (INVALID_SOCKET)
 #  endif /* !defined(_WIN32) || defined(_SYS_TYPES_FD_SET) */
 #endif /* MHD_INVALID_SOCKET */
 
 
 /**
  * Constant used to indicate unknown size (use when creating a response).
  * Any possible larger sizes are interpreted as the same value.
  */
 #ifdef UINT64_MAX
 #  define MHD_SIZE_UNKNOWN UINT64_MAX
 #else
 #  define MHD_SIZE_UNKNOWN \
         MHD_STATIC_CAST_ (uint_fast64_t,0xffffffffffffffffU)
 #endif
 
 
 /**
  * Constant used to indicate unlimited wait time.
  * Any possible larger values are interpreted as this value.
  */
 #ifdef UINT64_MAX
 #  define MHD_WAIT_INDEFINITELY UINT64_MAX
 #else
 #  define MHD_WAIT_INDEFINITELY \
         MHD_STATIC_CAST_ (uint_fast64_t,0xffffffffffffffffU)
 #endif
 
 
 /* ********** (a) Core HTTP Processing ************ */
 
 
 /**
  * @brief Handle for a daemon that listens for requests.
  *
  * Manages the listen socket, event loop, optional threads and server
  * settings.
  *
  * @defgroup daemon HTTP server handling client connections
  */
 struct MHD_Daemon;
 
 
 /**
  * @brief Handle/identifier of a network connection abstraction.
  *
  * A single network (i.e. TCP) connection can be used for
  * a single (in HTTP/1.1) data stream.
  *
  * @defgroup connection client connection with streams
  */
 struct MHD_Connection;
 
 
 /**
  * @brief Handle/identifier of a data stream over network
  * connection.
  *
  * A data stream may be used for multiple requests, which
  * in HTTP/1.1 must be processed sequentially.
  *
  * @defgroup stream stream of HTTP requests
  */
 struct MHD_Stream;
 
 /**
  * @brief Handle representing an HTTP request.
  *
  * With HTTP/1.1, multiple requests can be run over the same
  * stream.  However, MHD will only show one request per data
  * stream to the client at any given time.
  *
  * Replaces `struct MHD_Connection` in the API prior to version 2.0.0,
  * renamed to better reflect what this object truly represents to
  * the application using MHD.
  *
  * @defgroup request HTTP requests
  */
 struct MHD_Request;
 
 
 /**
  * @brief Actions are returned by the application when processed client header
  * to drive the request handling of MHD.
  *
  * @defgroup action Request actions
  */
 struct MHD_Action;
 
 
 /**
  * @brief Actions are returned by the application when processing client upload
  * to drive the request handling of MHD.
  *
  * @defgroup action Request actions
  */
 struct MHD_UploadAction;
 
 /**
  * @defgroup general Primary MHD functions and data
  */
 
 /**
  * @defgroup specialized Introspection and other special control
  */
 
 /**
  * @defgroup authentication Digest and other HTTP authentications
  */
 
 
 /**
  * Return values for reporting errors, also used for logging.
  *
  * A value of 0 indicates success (as a return value).
  * Values between 0 and 10000 must be handled explicitly by the app.
  * Values from 10000-19999 are informational.
  * Values from 20000-29999 indicate successful operations.
  * Values from 30000-39999 indicate unsuccessful (normal) operations.
  * Values from 40000-49999 indicate client errors.
  * Values from 50000-59999 indicate MHD server errors.
  * Values from 60000-65535 indicate application errors.
  *
  * @ingroup general
  */
 enum MHD_FIXED_ENUM_MHD_SET_ MHD_StatusCode
 {
 
   /* 00000-level status codes indicate return values
      the application must act on. */
 
   /**
    * Successful operation (not used for logging).
    * The code is guaranteed to be always zero.
    */
   MHD_SC_OK = 0
   ,
 
   /* 10000-level status codes indicate intermediate
      results of some kind. */
 
   /**
    * Informational event, MHD started.
    */
   MHD_SC_DAEMON_STARTED = 10000
   ,
   /**
    * Informational event, we accepted a connection.
    */
   MHD_SC_CONNECTION_ACCEPTED = 10001
   ,
   /**
    * Informational event, thread processing connection terminates.
    */
   MHD_SC_THREAD_TERMINATING = 10002
   ,
   /**
    * Informational event, state machine status for a connection.
    */
   MHD_SC_STATE_MACHINE_STATUS_REPORT = 10003
   ,
   /**
    * accept() returned transient error.
    */
   MHD_SC_ACCEPT_FAILED_EAGAIN = 10004
   ,
   /**
    * Accepted socket is unknown type (probably non-IP).
    */
   MHD_SC_ACCEPTED_UNKNOWN_TYPE = 10040
   ,
   /**
    * The sockaddr for the accepted socket does not fit the buffer.
    * (Strange)
    */
   MHD_SC_ACCEPTED_SOCKADDR_TOO_LARGE = 10041
   ,
 
   /* 20000-level status codes indicate success of some kind. */
 
   /**
    * MHD is closing a connection after the client closed it
    * (perfectly normal end).
    */
   MHD_SC_CONNECTION_CLOSED = 20000
   ,
   /**
    * MHD is closing a connection because the application
    * logic to generate the response data completed.
    */
   MHD_SC_APPLICATION_DATA_GENERATION_FINISHED = 20001
   ,
   /**
    * The request does not contain a particular type of Authentication
    * credentials
    */
   MHD_SC_AUTH_ABSENT = 20060
   ,
 
   /* 30000-level status codes indicate transient failures
      that might go away if the client tries again. */
 
 
   /**
    * Resource limit in terms of number of parallel connections
    * hit.
    */
   MHD_SC_LIMIT_CONNECTIONS_REACHED = 30000
   ,
   /**
    * The operation failed because the respective
    * daemon is already too deep inside of the shutdown
    * activity.
    */
   MHD_SC_DAEMON_ALREADY_SHUTDOWN = 30020
   ,
   /**
    * Failed to start new thread because of system limits.
    */
   MHD_SC_CONNECTION_THREAD_SYS_LIMITS_REACHED = 30030
   ,
   /**
    * Failed to start a thread.
    */
   MHD_SC_CONNECTION_THREAD_LAUNCH_FAILURE = 30031
   ,
   /**
    * The operation failed because we either have no
    * listen socket or were already quiesced.
    */
   MHD_SC_DAEMON_ALREADY_QUIESCED = 30040
   ,
   /**
    * The operation failed because client disconnected
    * faster than we could accept().
    */
   MHD_SC_ACCEPT_FAST_DISCONNECT = 30040
   ,
   /**
    * Operating resource limits hit on accept().
    */
   MHD_SC_ACCEPT_SYSTEM_LIMIT_REACHED = 30060
   ,
   /**
    * Connection was refused by accept policy callback.
    */
   MHD_SC_ACCEPT_POLICY_REJECTED = 30070
   ,
   /**
    * Failed to allocate memory for the daemon resources.
    * TODO: combine similar error codes for daemon
    */
   MHD_SC_DAEMON_MEM_ALLOC_FAILURE = 30081
   ,
   /**
    * We failed to allocate memory for the connection.
    * (May be transient.)
    */
   MHD_SC_CONNECTION_MEM_ALLOC_FAILURE = 30082
   ,
   /**
    * We failed to allocate memory for the connection's memory pool.
    * (May be transient.)
    */
   MHD_SC_POOL_MEM_ALLOC_FAILURE = 30083
   ,
   /**
    * We failed to allocate memory for the HTTP/2 connection's resources.
    * (May be transient.)
    */
   MHD_SC_H2_CONN_MEM_ALLOC_FAILURE = 30084
   ,
   /**
    * We failed to forward data from a Web socket to the
    * application to the remote side due to the socket
    * being closed prematurely. (May be transient.)
    */
   MHD_SC_UPGRADE_FORWARD_INCOMPLETE = 30100
   ,
   /**
    * Failed to allocate memory from our memory pool for processing
    * the request.  Likely the request fields are too large to leave
    * enough room.
    */
   MHD_SC_CONNECTION_POOL_NO_MEM_REQ = 30130
   ,
   /**
    * Failed to allocate memory from our memory pool to store GET parameter.
    * Likely the request URI or header fields are too large to leave enough room.
    */
   MHD_SC_CONNECTION_POOL_NO_MEM_GET_PARAM = 30131
   ,
   /**
    * Failed to allocate memory from our memory pool to store parsed cookie.
    */
   MHD_SC_CONNECTION_POOL_NO_MEM_COOKIE = 30132
   ,
   /**
    * Failed to allocate memory from connection memory pool to store
    * parsed Authentication data.
    */
   MHD_SC_CONNECTION_POOL_NO_MEM_AUTH_DATA = 30133
   ,
   /**
    * Detected jump back of system clock
    */
   MHD_SC_SYS_CLOCK_JUMP_BACK_LARGE = 30140
   ,
   /**
    * Detected correctable jump back of system clock
    */
   MHD_SC_SYS_CLOCK_JUMP_BACK_CORRECTED = 30141
   ,
   /**
    * Timeout waiting for communication operation for HTTP-Upgraded connection
    */
   MHD_SC_UPGRADED_NET_TIMEOUT = 30161
   ,
   /**
    * Not enough system resources
    */
   MHD_SC_NO_SYS_RESOURCES = 30180
   ,
 
   /* 40000-level errors are caused by the HTTP client
      (or the network) */
 
   /**
    * MHD is closing a connection because parsing the
    * request failed.
    */
   MHD_SC_CONNECTION_PARSE_FAIL_CLOSED = 40000
   ,
   /**
    * MHD is returning an error because the header provided
    * by the client is too big.
    */
   MHD_SC_CLIENT_HEADER_TOO_BIG = 40020
   ,
   /**
    * An HTTP/1.1 request was sent without the "Host:" header.
    */
   MHD_SC_HOST_HEADER_MISSING = 40060
   ,
   /**
    * Request has more than one "Host:" header.
    */
   MHD_SC_HOST_HEADER_SEVERAL = 40061
   ,
   /**
    * The value of the "Host:" header is invalid.
    */
   MHD_SC_HOST_HEADER_MALFORMED = 40062
   ,
   /**
    * The given content length was not a number.
    */
   MHD_SC_CONTENT_LENGTH_MALFORMED = 40065
   ,
   /**
    * Request has more than one "Content-Length:" header with the same value.
    */
   MHD_SC_CONTENT_LENGTH_SEVERAL_SAME = 40066
   ,
   /**
    * Request has more than one "Content-Length:" header with the different
    * values.
    */
   MHD_SC_CONTENT_LENGTH_SEVERAL_DIFFERENT = 40067
   ,
   /**
    * The BOTH Content-Length and Transfer-Encoding headers are used.
    */
   MHD_SC_CONTENT_LENGTH_AND_TR_ENC = 40068
   ,
   /**
    * The Content-Length is too large to be handled.
    */
   MHD_SC_CONTENT_LENGTH_TOO_LARGE = 40069
   ,
   /**
    * Transfer encoding in request is unsupported or invalid.
    */
   MHD_SC_TRANSFER_ENCODING_UNSUPPORTED = 40075
   ,
   /**
    * "Expect:" value in request is unsupported or invalid.
    */
   MHD_SC_EXPECT_HEADER_VALUE_UNSUPPORTED = 40076
   ,
   /**
    * The given uploaded, chunked-encoded body was malformed.
    */
   MHD_SC_CHUNKED_ENCODING_MALFORMED = 40080
   ,
   /**
    * The first header line has whitespace at the start
    */
   MHD_SC_REQ_FIRST_HEADER_LINE_SPACE_PREFIXED = 40100
   ,
   /**
    * The request target (URI) has whitespace character
    */
   MHD_SC_REQ_TARGET_HAS_WHITESPACE = 40101
   ,
   /**
    * Wrong bare CR characters has been replaced with space.
    */
   MHD_SC_REQ_HEADER_CR_REPLACED = 40120
   ,
   /**
    * Header line has not colon and skipped.
    */
   MHD_SC_REQ_HEADER_LINE_NO_COLON = 40121
   ,
   /**
    * Wrong bare CR characters has been replaced with space.
    */
   MHD_SC_REQ_FOOTER_CR_REPLACED = 40140
   ,
   /**
    * Footer line has not colon and skipped.
    */
   MHD_SC_REQ_FOOTER_LINE_NO_COLON = 40141
   ,
   /**
    * The request is malformed.
    */
   MHD_SC_REQ_MALFORMED = 40155
   ,
   /**
    * The cookie string has been parsed, but it is not fully compliant with
    * specifications
    */
   MHD_SC_REQ_COOKIE_PARSED_NOT_COMPLIANT = 40160
   ,
   /**
    * The cookie string has been parsed only partially
    */
   MHD_SC_REQ_COOKIE_PARSED_PARTIALLY = 40161
   ,
   /**
    * The cookie string is ignored, as it is not fully compliant with
    * specifications
    */
   MHD_SC_REQ_COOKIE_IGNORED_NOT_COMPLIANT = 40162
   ,
   /**
    * The cookie string has been ignored as it is invalid
    */
   MHD_SC_REQ_COOKIE_INVALID = 40163
   ,
   /**
    * The POST data parsed successfully, but has missing or incorrect
    * termination.
    * The last parsed field may have incorrect data.
    */
   MHD_SC_REQ_POST_PARSE_OK_BAD_TERMINATION = 40202
   ,
   /**
    * Parsing of the POST data is incomplete because client used incorrect
    * format of POST encoding.
    * Some POST data is available or has been provided via callback.
    */
   MHD_SC_REQ_POST_PARSE_PARTIAL_INVALID_POST_FORMAT = 40203
   ,
   /**
    * The request does not have "Content-Type:" header and POST data cannot
    * be parsed
    */
   MHD_SC_REQ_POST_PARSE_FAILED_NO_CNTN_TYPE = 40280
   ,
   /**
    * The request has unknown POST encoding specified by "Content-Type:" header
    */
   MHD_SC_REQ_POST_PARSE_FAILED_UNKNOWN_CNTN_TYPE = 40281
   ,
   /**
    * The request has "Content-Type: multipart/form-data" header without
    * "boundary" parameter
    */
   MHD_SC_REQ_POST_PARSE_FAILED_HEADER_NO_BOUNDARY = 40282
   ,
   /**
    * The request has "Content-Type: multipart/form-data" header with misformed
    * data
    */
   MHD_SC_REQ_POST_PARSE_FAILED_HEADER_MISFORMED = 40283
   ,
   /**
    * The POST data cannot be parsed because client used incorrect format
    * of POST encoding.
    */
   MHD_SC_REQ_POST_PARSE_FAILED_INVALID_POST_FORMAT = 40290
   ,
   /**
    * The data in Auth request header has invalid format.
    * For example, for Basic Authentication base64 decoding failed.
    */
   MHD_SC_REQ_AUTH_DATA_BROKEN = 40320
   ,
   /**
    * The request cannot be processed. Sending error reply.
    */
   MHD_SC_REQ_PROCCESSING_ERR_REPLY = 41000
   ,
   /**
    * MHD is closing a connection because of timeout.
    */
   MHD_SC_CONNECTION_TIMEOUT = 42000
   ,
   /**
    * MHD is closing a connection because receiving the
    * request failed.
    */
   MHD_SC_CONNECTION_RECV_FAIL_CLOSED = 42020
   ,
   /**
    * MHD is closing a connection because sending the response failed.
    */
   MHD_SC_CONNECTION_SEND_FAIL_CLOSED = 42021
   ,
   /**
    * MHD is closing a connection because remote client shut down its sending
    * side before full request was sent.
    */
   MHD_SC_CLIENT_SHUTDOWN_EARLY = 42040
   ,
   /**
    * MHD is closing a connection because remote client closed connection
    * early.
    */
   MHD_SC_CLIENT_CLOSED_CONN_EARLY = 42041
   ,
   /**
    * MHD is closing a connection connection has been (remotely) aborted.
    */
   MHD_SC_CONNECTION_ABORTED = 42042
   ,
   /**
    * MHD is closing a connection because it was reset.
    */
   MHD_SC_CONNECTION_RESET = 42060
   ,
   /**
    * MHD is closing a connection connection (or connection socket) has
    * been broken.
    */
   MHD_SC_CONNECTION_BROKEN = 42061
   ,
   /**
    * ALPN in TLS connection selected HTTP/2 (as advertised by the client),
    * but the client did not send a valid HTTP/2 connection preface.
    */
   MHD_SC_ALPN_H2_NO_PREFACE = 43001
   ,
 
   /* 50000-level errors are because of an error internal
      to the MHD logic, possibly including our interaction
      with the operating system (but not the application) */
 
   /**
    * This build of MHD does not support TLS, but the application
    * requested TLS.
    */
   MHD_SC_TLS_DISABLED = 50000
   ,
   /**
    * The selected TLS backend does not yet support this operation.
    */
   MHD_SC_TLS_BACKEND_OPERATION_UNSUPPORTED = 50004
   ,
   /**
    * Failed to setup ITC channel.
    */
   MHD_SC_ITC_INITIALIZATION_FAILED = 50005
   ,
   /**
    * File descriptor for ITC cannot be used because the FD number is higher
    * than the limit set by FD_SETSIZE (if internal polling with select is used)
    * or by application.
    */
   MHD_SC_ITC_FD_OUTSIDE_OF_SET_RANGE = 50006
   ,
   /**
    * The specified value for the NC length is way too large
    * for this platform (integer overflow on `size_t`).
    */
   MHD_SC_DIGEST_AUTH_NC_LENGTH_TOO_BIG = 50010
   ,
   /**
    * We failed to allocate memory for the specified nonce
    * counter array.  The option was not set.
    */
   MHD_SC_DIGEST_AUTH_NC_ALLOCATION_FAILURE = 50011
   ,
   /**
    * This build of the library does not support
    * digest authentication.
    */
   MHD_SC_DIGEST_AUTH_NOT_SUPPORTED_BY_BUILD = 50012
   ,
   /**
    * IPv6 requested but not supported by this build.
    * @sa #MHD_SC_AF_NOT_SUPPORTED_BY_BUILD
    */
   MHD_SC_IPV6_NOT_SUPPORTED_BY_BUILD = 50020
   ,
   /**
    * Specified address/protocol family is not supported by this build.
    * @sa MHD_SC_IPV6_NOT_SUPPORTED_BY_BUILD
    */
   MHD_SC_AF_NOT_SUPPORTED_BY_BUILD = 50021
   ,
   /**
    * The requested address/protocol family is rejected by the OS.
    * @sa #MHD_SC_AF_NOT_SUPPORTED_BY_BUILD
    */
   MHD_SC_AF_NOT_AVAILABLE = 500022
   ,
   /**
    * We failed to open the listen socket.
    */
   MHD_SC_FAILED_TO_OPEN_LISTEN_SOCKET = 50040
   ,
   /**
    * Failed to enable listen port reuse.
    */
   MHD_SC_LISTEN_PORT_REUSE_ENABLE_FAILED = 50041
   ,
   /**
    * Failed to enable listen port reuse.
    */
   MHD_SC_LISTEN_PORT_REUSE_ENABLE_NOT_SUPPORTED = 50042
   ,
   /**
    * Failed to enable listen address reuse.
    */
   MHD_SC_LISTEN_ADDRESS_REUSE_ENABLE_FAILED = 50043
   ,
   /**
    * Enabling listen address reuse is not supported by this platform.
    */
   MHD_SC_LISTEN_ADDRESS_REUSE_ENABLE_NOT_SUPPORTED = 50044
   ,
   /**
    * Failed to enable exclusive use of listen address.
    */
   MHD_SC_LISTEN_ADDRESS_EXCLUSIVE_ENABLE_FAILED = 50045
   ,
   /**
    * Dual stack configuration is not possible for provided sockaddr.
    */
   MHD_SC_LISTEN_DUAL_STACK_NOT_SUITABLE = 50046
   ,
   /**
    * Failed to enable or disable dual stack for the IPv6 listen socket.
    * The OS default dual-stack setting is different from what is requested.
    */
   MHD_SC_LISTEN_DUAL_STACK_CONFIGURATION_REJECTED = 50047
   ,
   /**
    * Failed to enable or disable dual stack for the IPv6 listen socket.
    * The socket will be used in whatever the default is the OS uses.
    */
   MHD_SC_LISTEN_DUAL_STACK_CONFIGURATION_UNKNOWN = 50048
   ,
   /**
    * On this platform, MHD does not support explicitly configuring
    * dual stack behaviour.
    */
   MHD_SC_LISTEN_DUAL_STACK_CONFIGURATION_NOT_SUPPORTED = 50049
   ,
   /**
    * Failed to enable TCP FAST OPEN option.
    */
   MHD_SC_LISTEN_FAST_OPEN_FAILURE = 50050
   ,
   /**
    * TCP FAST OPEN is not supported by the platform or by this MHD build.
    */
   MHD_SC_FAST_OPEN_NOT_SUPPORTED = 50051
   ,
   /**
    * We failed to set the listen socket to non-blocking.
    */
   MHD_SC_LISTEN_SOCKET_NONBLOCKING_FAILURE = 50052
   ,
   /**
    * Failed to configure listen socket to be non-inheritable.
    */
   MHD_SC_LISTEN_SOCKET_NOINHERIT_FAILED = 50053
   ,
   /**
    * Listen socket FD cannot be used because the FD number is higher than
    * the limit set by FD_SETSIZE (if internal polling with select is used) or
    * by application.
    */
   MHD_SC_LISTEN_FD_OUTSIDE_OF_SET_RANGE = 50054
   ,
   /**
    * We failed to bind the listen socket.
    */
   MHD_SC_LISTEN_SOCKET_BIND_FAILED = 50055
   ,
   /**
    * Failed to start listening on listen socket.
    */
   MHD_SC_LISTEN_FAILURE = 50056
   ,
   /**
    * Failed to detect the port number on the listening socket
    */
   MHD_SC_LISTEN_PORT_DETECT_FAILURE = 50057
   ,
   /**
    * We failed to create control socket for the epoll().
    */
   MHD_SC_EPOLL_CTL_CREATE_FAILED = 50060
   ,
   /**
    * We failed to configure control socket for the epoll()
    * to be non-inheritable.
    */
   MHD_SC_EPOLL_CTL_CONFIGURE_NOINHERIT_FAILED = 50061
   ,
   /**
    * The epoll() control FD cannot be used because the FD number is higher
    * than the limit set by application.
    */
   MHD_SC_EPOLL_CTL_OUTSIDE_OF_SET_RANGE = 50062
   ,
   /**
    * Failed to allocate memory for daemon's fd_sets
    */
   MHD_SC_FD_SET_MEMORY_ALLOCATE_FAILURE = 50063
   ,
   /**
    * Failed to allocate memory for poll() structures
    */
   MHD_SC_POLL_FDS_MEMORY_ALLOCATE_FAILURE = 50063
   ,
   /**
    * Failed to allocate memory for epoll data
    */
   MHD_SC_EPOLL_EVENTS_MEMORY_ALLOCATE_FAILURE = 50064
   ,
   /**
    * Failed to add daemon's FDs (ITC and/or listening) to the epoll monitoring
    */
   MHD_SC_EPOLL_ADD_DAEMON_FDS_FAILURE = 50065
   ,
   /**
    * Failed to register daemon's FDs (ITC or listening) in the application
    * (external event) monitoring
    */
   MHD_SC_EXT_EVENT_REG_DAEMON_FDS_FAILURE = 50066
   ,
   /**
    * The select() syscall is not available on this platform or in this MHD
    * build.
    */
   MHD_SC_SELECT_SYSCALL_NOT_AVAILABLE = 50070
   ,
   /**
    * The poll() syscall is not available on this platform or in this MHD
    * build.
    */
   MHD_SC_POLL_SYSCALL_NOT_AVAILABLE = 50071
   ,
   /**
    * The epoll syscalls are not available on this platform or in this MHD
    * build.
    */
   MHD_SC_EPOLL_SYSCALL_NOT_AVAILABLE = 50072
   ,
   /**
    * Failed to obtain our listen port via introspection.
    * FIXME: remove?
    */
   MHD_SC_LISTEN_PORT_INTROSPECTION_FAILURE = 50080
   ,
   /**
    * Failed to obtain our listen port via introspection
    * due to unsupported address family being used.
    */
   MHD_SC_LISTEN_PORT_INTROSPECTION_UNKNOWN_AF = 50081
   ,
   /**
    * Failed to initialise mutex.
    */
   MHD_SC_MUTEX_INIT_FAILURE = 50085
   ,
   /**
    * Failed to allocate memory for the thread pool.
    */
   MHD_SC_THREAD_POOL_MEM_ALLOC_FAILURE = 50090
   ,
   /**
    * We failed to allocate mutex for thread pool worker.
    */
   MHD_SC_THREAD_POOL_CREATE_MUTEX_FAILURE = 50093
   ,
   /**
    * Failed to start the main daemon thread.
    */
   MHD_SC_THREAD_MAIN_LAUNCH_FAILURE = 50095
   ,
   /**
    * Failed to start the daemon thread for listening.
    */
   MHD_SC_THREAD_LISTENING_LAUNCH_FAILURE = 50096
   ,
   /**
    * Failed to start the worker thread for the thread pool.
    */
   MHD_SC_THREAD_WORKER_LAUNCH_FAILURE = 50097
   ,
   /**
    * There was an attempt to upgrade a connection on
    * a daemon where upgrades are disallowed.
    */
   MHD_SC_UPGRADE_ON_DAEMON_WITH_UPGRADE_DISALLOWED = 50100
   ,
   /**
    * Failed to signal via ITC channel.
    */
   MHD_SC_ITC_USE_FAILED = 500101
   ,
   /**
    * Failed to check for the signal on the ITC channel.
    */
   MHD_SC_ITC_CHECK_FAILED = 500102
   ,
   /**
    * System reported error conditions on the ITC FD.
    */
   MHD_SC_ITC_STATUS_ERROR = 500104
   ,
   /**
    * Failed to add a socket to the epoll set.
    */
   MHD_SC_EPOLL_CTL_ADD_FAILED = 500110
   ,
   /**
    * Socket FD cannot be used because the FD number is higher than the limit set
    * by FD_SETSIZE (if internal polling with select is used) or by application.
    */
   MHD_SC_SOCKET_OUTSIDE_OF_SET_RANGE = 500111
   ,
   /**
    * The daemon cannot be started with the specified settings as no space
    * left for the connections sockets within limits set by FD_SETSIZE.
    * Consider use another sockets polling syscall (only select() has such
    * limitations)
    */
   MHD_SC_SYS_FD_SETSIZE_TOO_STRICT = 50112
   ,
   /**
    * This daemon was not configured with options that
    * would allow us to obtain a meaningful timeout.
    */
   MHD_SC_CONFIGURATION_MISMATCH_FOR_GET_TIMEOUT = 50113
   ,
   /**
    * This daemon was not configured with options that
    * would allow us to run with select() data.
    */
   MHD_SC_CONFIGURATION_MISMATCH_FOR_RUN_SELECT = 50114
   ,
   /**
    * This daemon was not configured to run with an
    * external event loop.
    */
   MHD_SC_CONFIGURATION_MISMATCH_FOR_RUN_EXTERNAL = 50115
   ,
   /**
    * Encountered an unexpected error from select()
    * (should never happen).
    */
   MHD_SC_UNEXPECTED_SELECT_ERROR = 50116
   ,
   /**
    * Failed to remove a socket to the epoll set.
    */
   MHD_SC_EPOLL_CTL_REMOVE_FAILED = 50117
   ,
   /**
    * poll() is not supported.
    */
   MHD_SC_POLL_NOT_SUPPORTED = 50120
   ,
   /**
    * Encountered a (potentially) recoverable error from poll().
    */
   MHD_SC_POLL_SOFT_ERROR = 50121
   ,
   /**
    * Encountered an unrecoverable error from poll().
    */
   MHD_SC_POLL_HARD_ERROR = 50122
   ,
   /**
    * Encountered a (potentially) recoverable error from select().
    */
   MHD_SC_SELECT_SOFT_ERROR = 50123
   ,
   /**
    * Encountered an unrecoverable error from select().
    */
   MHD_SC_SELECT_HARD_ERROR = 50124
   ,
   /**
    * System reported error conditions on the listening socket.
    */
   MHD_SC_LISTEN_STATUS_ERROR = 50129
   ,
   /**
    * Encountered an unrecoverable error from epoll function.
    */
   MHD_SC_EPOLL_HARD_ERROR = 50130
   ,
   /**
    * We failed to configure accepted socket
    * to not use a SIGPIPE.
    */
   MHD_SC_ACCEPT_CONFIGURE_NOSIGPIPE_FAILED = 50140
   ,
   /**
    * We failed to configure accepted socket
    * to be non-inheritable.
    */
   MHD_SC_ACCEPT_CONFIGURE_NOINHERIT_FAILED = 50141
   ,
   /**
    * We failed to configure accepted socket
    * to be non-blocking.
    */
   MHD_SC_ACCEPT_CONFIGURE_NONBLOCKING_FAILED = 50142
   ,
   /**
    * The accepted socket FD value is too large.
    */
   MHD_SC_ACCEPT_OUTSIDE_OF_SET_RANGE = 50143
   ,
   /**
    * accept() returned unexpected error.
    */
   MHD_SC_ACCEPT_FAILED_UNEXPECTEDLY = 50144
   ,
   /**
    * Operating resource limits hit on accept() while
    * zero connections are active. Oopsie.
    */
   MHD_SC_ACCEPT_SYSTEM_LIMIT_REACHED_INSTANTLY = 50145
   ,
   /**
    * The daemon sockets polling mode requires non-blocking sockets.
    */
   MHD_SC_NONBLOCKING_REQUIRED = 50146
   ,
   /**
    * Encountered an unexpected error from epoll_wait()
    * (should never happen).
    */
   MHD_SC_UNEXPECTED_EPOLL_WAIT_ERROR = 50150
   ,
   /**
    * epoll file descriptor is invalid (strange)
    */
   MHD_SC_EPOLL_FD_INVALID = 50151
   ,
   /**
    * Unexpected socket error (strange)
    */
   MHD_SC_UNEXPECTED_SOCKET_ERROR = 50152
   ,
   /**
    * Failed to add IP address to per-IP counter for
    * some reason.
    */
   MHD_SC_IP_COUNTER_FAILURE = 50160
   ,
   /**
    * Application violated our API by calling shutdown
    * while having an upgrade connection still open.
    */
   MHD_SC_SHUTDOWN_WITH_OPEN_UPGRADED_CONNECTION = 50180
   ,
   /**
    * Due to an unexpected internal error with the
    * state machine, we closed the connection.
    */
   MHD_SC_STATEMACHINE_FAILURE_CONNECTION_CLOSED = 50200
   ,
   /**
    * Failed to allocate memory in connection's pool
    * to parse the cookie header.
    */
   MHD_SC_COOKIE_POOL_ALLOCATION_FAILURE = 50220
   ,
   /**
    * MHD failed to build the response header.
    */
   MHD_SC_REPLY_FAILED_HEADER_GENERATION = 50230
   ,
   /**
    * Failed to allocate memory in connection's pool for the reply.
    */
   MHD_SC_REPLY_POOL_ALLOCATION_FAILURE = 50231
   ,
   /**
    * Failed to read the file for file-backed response.
    */
   MHD_SC_REPLY_FILE_READ_ERROR = 50232
   ,
   /**
    * Failed to generate the nonce for the Digest Auth.
    */
   MHD_SC_REPLY_NONCE_ERROR = 50233
   ,
   /**
    * Failed to allocate memory in connection's pool for the reply.
    */
   MHD_SC_ERR_RESPONSE_ALLOCATION_FAILURE = 50250
   ,
   /**
    * The request POST data cannot be parsed because stream has not enough
    * pool memory free.
    */
   MHD_SC_REQ_POST_PARSE_FAILED_NO_POOL_MEM = 50260
   ,
   /**
    * The POST data cannot be parsed completely because no "large shared buffer"
    * space is available.
    * Some POST data may be parsed.
    */
   MHD_SC_REQ_POST_PARSE_FAILED_NO_LARGE_BUF_MEM = 50261
   ,
   /**
    * The application set POST encoding to "multipart/form-data", but the request
    * has no "Content-Type: multipart/form-data" header which is required
    * to find "boundary" used in this encoding
    */
   MHD_SC_REQ_POST_PARSE_FAILED_HEADER_NOT_MPART = 50284
   ,
   /**
    * The feature is not supported by this MHD build (either
    * disabled by configure parameters or build platform
    * did not support it, because headers are missing or
    * so kernel does not have such feature).
    * The feature will not be enabled if the same MHD binary
    * will be run on another kernel, computer or system
    * configuration.
    */
   MHD_SC_FEATURE_DISABLED = 50300
   ,
   /**
    * The feature is not supported by this platform, while
    * supported by MHD build.
    * The feature can be enabled by changing the kernel or
    * running on another computer or with other system
    * configuration.
    */
   MHD_SC_FEATURE_NOT_AVAILABLE = 50320
   ,
   /**
    * Failed to stop the thread
    */
   MHD_SC_DAEMON_THREAD_STOP_ERROR = 50350
   ,
   /**
    * Unexpected reasons for thread stop
    */
   MHD_SC_DAEMON_THREAD_STOP_UNEXPECTED = 50351
   ,
   /**
    * Daemon system data is broken (like listen socket was unexpectedly closed).
    * The daemon needs to be closed.
    * A new daemon can be started as a replacement after closing the current
    * daemon.
    */
   MHD_SC_DAEMON_SYS_DATA_BROKEN = 50370
   ,
   /**
    * Failed to acquire response mutex lock
    */
   MHD_SC_RESPONSE_MUTEX_LOCK_FAILED = 50500
   ,
   /**
    * Failed to initialise response mutex
    */
   MHD_SC_RESPONSE_MUTEX_INIT_FAILED = 50501
   ,
   /**
    * Unable to clear "reusable" flag.
    * One this flag set, it cannot be removed for the response lifetime.
    */
   MHD_SC_RESPONSE_CANNOT_CLEAR_REUSE = 50520
   ,
   /**
    * Unable to allocate memory for the response header
    */
   MHD_SC_RESPONSE_HEADER_MEM_ALLOC_FAILED = 50540
   ,
   /**
    * Failed to switch TCP_NODELAY option for the socket
    */
   MHD_SC_SOCKET_TCP_NODELAY_FAILED = 50600
   ,
   /**
    * Failed to switch TCP_CORK or TCP_NOPUSH option for the socket
    */
   MHD_SC_SOCKET_TCP_CORK_NOPUSH_FAILED = 50601
   ,
   /**
    * Failed to force flush the last part of the response header or
    * the response content
    */
   MHD_SC_SOCKET_FLUSH_LAST_PART_FAILED = 50620
   ,
   /**
    * Failed to push buffered data by zero-sized send()
    */
   MHD_SC_SOCKET_ZERO_SEND_FAILED = 50621
   ,
   /**
    * The HTTP-Upgraded network connection has been closed / disconnected
    */
   MHD_SC_UPGRADED_NET_CONN_CLOSED = 50800
   ,
   /**
    * The HTTP-Upgraded network connection has been broken
    */
   MHD_SC_UPGRADED_NET_CONN_BROKEN = 50801
   ,
   /**
    * The TLS communication error on HTTP-Upgraded connection
    */
   MHD_SC_UPGRADED_TLS_ERROR = 50801
   ,
   /**
    * Unrecoverable sockets communication error on HTTP-Upgraded connection
    */
   MHD_SC_UPGRADED_NET_HARD_ERROR = 50840
   ,
   /**
    * MHD cannot wait for the data on the HTTP-Upgraded connection, because
    * current build or the platform does not support required functionality.
    * Communication with zero timeout is fully supported.
    */
   MHD_SC_UPGRADED_WAITING_NOT_SUPPORTED = 50840
   ,
   /**
    * Global initialisation of MHD library failed
    */
   MHD_SC_LIB_INIT_GLOBAL_FAILED = 51000
   ,
   /**
    * Failed to initialise TLS context for the daemon
    */
   MHD_SC_TLS_DAEMON_INIT_FAILED = 51200
   ,
   /**
    * Failed to initialise TLS context for the new connection
    */
   MHD_SC_TLS_CONNECTION_INIT_FAILED = 51201
   ,
   /**
    * Warning about TLS backend configuration
    */
   MHD_SC_TLS_LIB_CONF_WARNING = 51202
   ,
   /**
    * Failed to perform TLS handshake
    */
   MHD_SC_TLS_CONNECTION_HANDSHAKED_FAILED = 51220
   ,
   /**
    * Hashing failed.
    * Internal hashing function can never fail (and this code is never returned
    * for them). External hashing function (like TLS backend-based) may fail
    * for various reasons, like failure of hardware acccelerated hashing.
    */
   MHD_SC_HASH_FAILED = 51260
   ,
   /**
    * Something wrong in the internal MHD logic.
    * This error should be never returned if MHD works as expected.
    * If this code is ever returned, please report to MHD maintainers.
    */
   MHD_SC_INTERNAL_ERROR = 59900
   ,
 
   /* 60000-level errors are because the application
      logic did something wrong or generated an error. */
 
   /**
    * The application called function too early.
    * For example, a header value was requested before the headers
    * had been received.
    */
   MHD_SC_TOO_EARLY = 60000
   ,
   /**
    * The application called this function too late.
    * For example, MHD has already started sending reply.
    */
   MHD_SC_TOO_LATE = 60001
   ,
   /**
    * MHD does not support the requested combination of
    * the sockets polling syscall and the work mode.
    */
   MHD_SC_SYSCALL_WORK_MODE_COMBINATION_INVALID = 60010
   ,
   /**
    * MHD does not support quiescing if ITC was disabled
    * and threads are used.
    */
   MHD_SC_SYSCALL_QUIESCE_REQUIRES_ITC = 60011
   ,
   /**
    * The option provided or function called can be used only with "external
    * events" modes.
    */
   MHD_SC_EXTERNAL_EVENT_ONLY = 60012
   ,
   /**
    * MHD is closing a connection because the application
    * logic to generate the response data failed.
    */
   MHD_SC_APPLICATION_DATA_GENERATION_FAILURE_CLOSED = 60015
   ,
   /**
    * MHD is closing a connection because the application
    * callback told it to do so.
    */
   MHD_SC_APPLICATION_CALLBACK_ABORT_ACTION = 60016
   ,
   /**
    * Application only partially processed upload and did
    * not suspend connection. This may result in a hung
    * connection.
    */
   MHD_SC_APPLICATION_HUNG_CONNECTION = 60017
   ,
   /**
    * Application only partially processed upload and did
    * not suspend connection and the read buffer was maxxed
    * out, so MHD closed the connection.
    */
   MHD_SC_APPLICATION_HUNG_CONNECTION_CLOSED = 60018
   ,
   /**
    * Attempted to set an option that conflicts with another option
    * already set.
    */
   MHD_SC_OPTIONS_CONFLICT = 60020
   ,
   /**
    * Attempted to set an option that not recognised by MHD.
    */
   MHD_SC_OPTION_UNKNOWN = 60021
   ,
   /**
    * Parameter specified unknown work mode.
    */
   MHD_SC_CONFIGURATION_UNEXPECTED_WM = 60022
   ,
   /**
    * Parameter specified unknown Sockets Polling Syscall (SPS).
    */
   MHD_SC_CONFIGURATION_UNEXPECTED_SPS = 60023
   ,
   /**
    * The size of the provided sockaddr does not match address family.
    */
   MHD_SC_CONFIGURATION_WRONG_SA_SIZE = 60024
   ,
   /**
    * The number set by #MHD_D_O_FD_NUMBER_LIMIT is too strict to run
    * the daemon
    */
   MHD_SC_MAX_FD_NUMBER_LIMIT_TOO_STRICT = 60025
   ,
   /**
    * The number set by #MHD_D_O_GLOBAL_CONNECTION_LIMIT is too for the daemon
    * configuration
    */
   MHD_SC_CONFIGURATION_CONN_LIMIT_TOO_SMALL = 60026
   ,
   /**
    * The provided configuration parameter is NULL, but it must be non-NULL
    */
   MHD_SC_CONFIGURATION_PARAM_NULL = 60027
   ,
   /**
    * The size of the provided configuration parameter is too large
    */
   MHD_SC_CONFIGURATION_PARAM_TOO_LARGE = 60028
   ,
   /**
    * The application requested an unsupported TLS backend to be used.
    */
   MHD_SC_TLS_BACKEND_UNSUPPORTED = 60030
   ,
   /**
    * The application attempted to setup TLS parameters before
    * enabling TLS.
    */
   MHD_SC_TLS_BACKEND_UNINITIALIZED = 60031
   ,
   /**
    * The application requested a TLS backend which cannot be used due
    * to missing TLS dynamic library or backend initialisation problem.
    */
   MHD_SC_TLS_BACKEND_UNAVAILABLE = 60032
   ,
   /**
    * Provided TLS certificate and/or private key are incorrect
    */
   MHD_SC_TLS_CONF_BAD_CERT = 60033
   ,
   /**
    * The application requested a daemon setting that cannot be used with
    * selected TLS backend
    */
   MHD_SC_TLS_BACKEND_DAEMON_INCOMPATIBLE_SETTINGS = 60034
   ,
   /**
    * The response header name has forbidden characters or token
    */
   MHD_SC_RESP_HEADER_NAME_INVALID = 60050
   ,
   /**
    * The response header value has forbidden characters or token
    */
   MHD_SC_RESP_HEADER_VALUE_INVALID = 60051
   ,
   /**
    * An attempt to add header conflicting with other response header
    */
   MHD_SC_RESP_HEADERS_CONFLICT = 60052
   ,
   /**
    * The pointer to the response object is NULL
    */
   MHD_SC_RESP_POINTER_NULL = 60060
   ,
   /**
    * The response HTTP status code is not suitable
    */
   MHD_SC_RESP_HTTP_CODE_NOT_SUITABLE = 60061
   ,
   /**
    * The provided MHD_Action is invalid
    */
   MHD_SC_ACTION_INVALID = 60080
   ,
   /**
    * The provided MHD_UploadAction is invalid
    */
   MHD_SC_UPLOAD_ACTION_INVALID = 60081
   ,
   /**
    * The provided Dynamic Content Creator action is invalid
    */
   MHD_SC_DCC_ACTION_INVALID = 60082
   ,
   /**
    * The response must be empty
    */
   MHD_SC_REPLY_NOT_EMPTY_RESPONSE = 60101
   ,
   /**
    * The "Content-Length" header is not allowed in the reply
    */
   MHD_SC_REPLY_CONTENT_LENGTH_NOT_ALLOWED = 60102
   ,
   /**
    * The provided reply headers do not fit the connection buffer
    */
   MHD_SC_REPLY_HEADERS_TOO_LARGE = 60103
   ,
   /**
    * Specified offset in file-backed response is too large and not supported
    * by the platform
    */
   MHD_SC_REPLY_FILE_OFFSET_TOO_LARGE = 60104
   ,
   /**
    * File-backed response has file smaller than specified combination of
    * the file offset and the response size.
    */
   MHD_SC_REPLY_FILE_TOO_SHORT = 60105
   ,
   /**
    * The new connection cannot be used because the FD number is higher than
    * the limit set by FD_SETSIZE (if internal polling with select is used) or
    * by application.
    */
   MHD_SC_NEW_CONN_FD_OUTSIDE_OF_SET_RANGE = 60140
   ,
   /**
    * The daemon is being destroyed, while not all HTTP-Upgraded connections
    * has been closed.
    */
   MHD_SC_DAEMON_DESTROYED_WITH_UNCLOSED_UPGRADED = 60160
   ,
   /**
    * The provided pointer to 'struct MHD_UpgradedHandle' is invalid
    */
   MHD_SC_UPGRADED_HANDLE_INVALID = 60161
   ,
   /**
    * The provided output buffer is too small.
    */
   MHD_SC_OUT_BUFF_TOO_SMALL = 60180
   ,
   /**
    * The requested type of information is not recognised.
    */
   MHD_SC_INFO_GET_TYPE_UNKNOWN = 60200
   ,
   /**
    * The information of the requested type is too large to fit into
    * the provided buffer.
    */
   MHD_SC_INFO_GET_BUFF_TOO_SMALL = 60201
   ,
   /**
    * The type of the information is not supported by this MHD build.
    * It can be information not supported on the current platform or related
    * to feature disabled for this build.
    */
   MHD_SC_INFO_GET_TYPE_NOT_SUPP_BY_BUILD = 60202
   ,
   /**
    * The type of the information is not available due to configuration
    * or state of the object.
    */
   MHD_SC_INFO_GET_TYPE_NOT_APPLICABLE = 60203
   ,
   /**
    * The type of the information should be available for the object, but
    * cannot be provided due to some error or other reasons.
    */
   MHD_SC_INFO_GET_TYPE_UNOBTAINABLE = 60204
   ,
   /**
    * The type of the Digest Auth algorithm is unknown or not supported.
    */
   MHD_SC_AUTH_DIGEST_ALGO_NOT_SUPPORTED = 60240
   ,
   /**
    * The Digest Auth QOP value is unknown or not supported.
    */
   MHD_SC_AUTH_DIGEST_QOP_NOT_SUPPORTED = 60241
   ,
   /**
    * The Digest Auth is not supported due to configuration
    */
   MHD_SC_AUTH_DIGEST_UNSUPPORTED = 60242
   ,
   /**
    * The application failed to register FD for the external events monitoring
    */
   MHD_SC_EXTR_EVENT_REG_FAILED = 60243
   ,
   /**
    * The application failed to de-register FD for the external events monitoring
    */
   MHD_SC_EXTR_EVENT_DEREG_FAILED = 60244
   ,
   /**
    * The application called #MHD_daemon_event_update() with broken data
    */
   MHD_SC_EXTR_EVENT_BROKEN_DATA = 60250
   ,
   /**
    * The application called #MHD_daemon_event_update() with status that
    * has not been requested
    */
   MHD_SC_EXTR_EVENT_UNEXPECTED_STATUS = 60251
 };
 
 /**
  * Get text description for the MHD error code.
  *
  * This function works for @b MHD error codes, not for @b HTTP status codes.
  * @param code the MHD code to get description for
  * @return the pointer to the text description,
  *         NULL if MHD code in not known.
  *
  * @ingroup general
  */
 MHD_EXTERN_ const struct MHD_String *
 MHD_status_code_to_string (enum MHD_StatusCode code)
 MHD_FN_CONST_;
 
 /**
  * Get the pointer to the C string for the MHD error code, never NULL.
  */
 #define MHD_status_code_to_string_lazy(code) \
         (MHD_status_code_to_string ((code)) ? \
          ((MHD_status_code_to_string (code))->cstr) : ("[No code]") )
 
 #ifndef MHD_HTTP_METHOD_DEFINED
 
 /**
  * @brief HTTP request methods
  *
  * @defgroup methods HTTP methods
  *
  * See: https://www.iana.org/assignments/http-methods/http-methods.xml
  * Registry export date: 2023-10-02
  * @{
  */
 
 /**
  * HTTP methods explicitly supported by MHD.  Note that for non-canonical
  * methods, MHD will return #MHD_HTTP_METHOD_OTHER and you can use
  * #MHD_REQUEST_INFO_FIXED_HTTP_METHOD to get the original string.
  *
  * However, applications must check for #MHD_HTTP_METHOD_OTHER *or* any enum-value
  * above those in this list, as future versions of MHD may add additional
  * methods (as per IANA registry), thus even if the API returns
  * #MHD_HTTP_METHOD_OTHER today, it may return a method-specific header in the
  * future!
  */
 enum MHD_FIXED_ENUM_MHD_SET_ MHD_HTTP_Method
 {
 
   /**
    * Method did not match any of the methods given below.
    */
   MHD_HTTP_METHOD_OTHER = 255
   ,
   /* Main HTTP methods. */
 
   /**
    * "GET"
    * Safe.     Idempotent.     RFC9110, Section 9.3.1.
    */
   MHD_HTTP_METHOD_GET = 1
   ,
   /**
    * "HEAD"
    * Safe.     Idempotent.     RFC9110, Section 9.3.2.
    */
   MHD_HTTP_METHOD_HEAD = 2
   ,
   /**
    * "POST"
    * Not safe. Not idempotent. RFC9110, Section 9.3.3.
    */
   MHD_HTTP_METHOD_POST = 3
   ,
   /**
    * "PUT"
    * Not safe. Idempotent.     RFC9110, Section 9.3.4.
    */
   MHD_HTTP_METHOD_PUT = 4
   ,
   /**
    * "DELETE"
    * Not safe. Idempotent.     RFC9110, Section 9.3.5.
    */
   MHD_HTTP_METHOD_DELETE = 5
   ,
   /**
    * "CONNECT"
    * Not safe. Not idempotent. RFC9110, Section 9.3.6.
    */
   MHD_HTTP_METHOD_CONNECT = 6
   ,
   /**
    * "OPTIONS"
    * Safe.     Idempotent.     RFC9110, Section 9.3.7.
    */
   MHD_HTTP_METHOD_OPTIONS = 7
   ,
   /**
    * "TRACE"
    * Safe.     Idempotent.     RFC9110, Section 9.3.8.
    */
   MHD_HTTP_METHOD_TRACE = 8
   ,
   /**
    * "*"
    * Not safe. Not idempotent. RFC9110, Section 18.2.
    */
   MHD_HTTP_METHOD_ASTERISK = 9
 };
 
 #define MHD_HTTP_METHOD_DEFINED 1
 #endif /* ! MHD_HTTP_METHOD_DEFINED */
 
 /**
  * Get text version of the method name.
  * @param method the method to get the text version
  * @return the pointer to the text version,
  *         NULL if method is MHD_HTTP_METHOD_OTHER
  *         or not known.
  */
 MHD_EXTERN_ const struct MHD_String *
 MHD_http_method_to_string (enum MHD_HTTP_Method method)
 MHD_FN_CONST_;
 
 
 /* Main HTTP methods. */
 /* Safe.     Idempotent.     RFC9110, Section 9.3.1. */
 #define MHD_HTTP_METHOD_STR_GET      "GET"
 /* Safe.     Idempotent.     RFC9110, Section 9.3.2. */
 #define MHD_HTTP_METHOD_STR_HEAD     "HEAD"
 /* Not safe. Not idempotent. RFC9110, Section 9.3.3. */
 #define MHD_HTTP_METHOD_STR_POST     "POST"
 /* Not safe. Idempotent.     RFC9110, Section 9.3.4. */
 #define MHD_HTTP_METHOD_STR_PUT      "PUT"
 /* Not safe. Idempotent.     RFC9110, Section 9.3.5. */
 #define MHD_HTTP_METHOD_STR_DELETE   "DELETE"
 /* Not safe. Not idempotent. RFC9110, Section 9.3.6. */
 #define MHD_HTTP_METHOD_STR_CONNECT  "CONNECT"
 /* Safe.     Idempotent.     RFC9110, Section 9.3.7. */
 #define MHD_HTTP_METHOD_STR_OPTIONS  "OPTIONS"
 /* Safe.     Idempotent.     RFC9110, Section 9.3.8. */
 #define MHD_HTTP_METHOD_STR_TRACE    "TRACE"
 /* Not safe. Not idempotent. RFC9110, Section 18.2. */
 #define MHD_HTTP_METHOD_STR_ASTERISK  "*"
 
 /* Additional HTTP methods. */
 /* Not safe. Idempotent.     RFC3744, Section 8.1. */
 #define MHD_HTTP_METHOD_STR_ACL            "ACL"
 /* Not safe. Idempotent.     RFC3253, Section 12.6. */
 #define MHD_HTTP_METHOD_STR_BASELINE_CONTROL "BASELINE-CONTROL"
 /* Not safe. Idempotent.     RFC5842, Section 4. */
 #define MHD_HTTP_METHOD_STR_BIND           "BIND"
 /* Not safe. Idempotent.     RFC3253, Section 4.4, Section 9.4. */
 #define MHD_HTTP_METHOD_STR_CHECKIN        "CHECKIN"
 /* Not safe. Idempotent.     RFC3253, Section 4.3, Section 8.8. */
 #define MHD_HTTP_METHOD_STR_CHECKOUT       "CHECKOUT"
 /* Not safe. Idempotent.     RFC4918, Section 9.8. */
 #define MHD_HTTP_METHOD_STR_COPY           "COPY"
 /* Not safe. Idempotent.     RFC3253, Section 8.2. */
 #define MHD_HTTP_METHOD_STR_LABEL          "LABEL"
 /* Not safe. Idempotent.     RFC2068, Section 19.6.1.2. */
 #define MHD_HTTP_METHOD_STR_LINK           "LINK"
 /* Not safe. Not idempotent. RFC4918, Section 9.10. */
 #define MHD_HTTP_METHOD_STR_LOCK           "LOCK"
 /* Not safe. Idempotent.     RFC3253, Section 11.2. */
 #define MHD_HTTP_METHOD_STR_MERGE          "MERGE"
 /* Not safe. Idempotent.     RFC3253, Section 13.5. */
 #define MHD_HTTP_METHOD_STR_MKACTIVITY     "MKACTIVITY"
 /* Not safe. Idempotent.     RFC4791, Section 5.3.1; RFC8144, Section 2.3. */
 #define MHD_HTTP_METHOD_STR_MKCALENDAR     "MKCALENDAR"
 /* Not safe. Idempotent.     RFC4918, Section 9.3; RFC5689, Section 3; RFC8144, Section 2.3. */
 #define MHD_HTTP_METHOD_STR_MKCOL          "MKCOL"
 /* Not safe. Idempotent.     RFC4437, Section 6. */
 #define MHD_HTTP_METHOD_STR_MKREDIRECTREF  "MKREDIRECTREF"
 /* Not safe. Idempotent.     RFC3253, Section 6.3. */
 #define MHD_HTTP_METHOD_STR_MKWORKSPACE    "MKWORKSPACE"
 /* Not safe. Idempotent.     RFC4918, Section 9.9. */
 #define MHD_HTTP_METHOD_STR_MOVE           "MOVE"
 /* Not safe. Idempotent.     RFC3648, Section 7. */
 #define MHD_HTTP_METHOD_STR_ORDERPATCH     "ORDERPATCH"
 /* Not safe. Not idempotent. RFC5789, Section 2. */
 #define MHD_HTTP_METHOD_STR_PATCH          "PATCH"
 /* Safe.     Idempotent.     RFC9113, Section 3.4. */
 #define MHD_HTTP_METHOD_STR_PRI            "PRI"
 /* Safe.     Idempotent.     RFC4918, Section 9.1; RFC8144, Section 2.1. */
 #define MHD_HTTP_METHOD_STR_PROPFIND       "PROPFIND"
 /* Not safe. Idempotent.     RFC4918, Section 9.2; RFC8144, Section 2.2. */
 #define MHD_HTTP_METHOD_STR_PROPPATCH      "PROPPATCH"
 /* Not safe. Idempotent.     RFC5842, Section 6. */
 #define MHD_HTTP_METHOD_STR_REBIND         "REBIND"
 /* Safe.     Idempotent.     RFC3253, Section 3.6; RFC8144, Section 2.1. */
 #define MHD_HTTP_METHOD_STR_REPORT         "REPORT"
 /* Safe.     Idempotent.     RFC5323, Section 2. */
 #define MHD_HTTP_METHOD_STR_SEARCH         "SEARCH"
 /* Not safe. Idempotent.     RFC5842, Section 5. */
 #define MHD_HTTP_METHOD_STR_UNBIND         "UNBIND"
 /* Not safe. Idempotent.     RFC3253, Section 4.5. */
 #define MHD_HTTP_METHOD_STR_UNCHECKOUT     "UNCHECKOUT"
 /* Not safe. Idempotent.     RFC2068, Section 19.6.1.3. */
 #define MHD_HTTP_METHOD_STR_UNLINK         "UNLINK"
 /* Not safe. Idempotent.     RFC4918, Section 9.11. */
 #define MHD_HTTP_METHOD_STR_UNLOCK         "UNLOCK"
 /* Not safe. Idempotent.     RFC3253, Section 7.1. */
 #define MHD_HTTP_METHOD_STR_UPDATE         "UPDATE"
 /* Not safe. Idempotent.     RFC4437, Section 7. */
 #define MHD_HTTP_METHOD_STR_UPDATEREDIRECTREF "UPDATEREDIRECTREF"
 /* Not safe. Idempotent.     RFC3253, Section 3.5. */
 #define MHD_HTTP_METHOD_STR_VERSION_CONTROL "VERSION-CONTROL"
 
 /** @} */ /* end of group methods */
 
 #ifndef MHD_HTTP_POSTENCODING_DEFINED
 
 
 /**
  * @brief Possible encodings for HTML forms submitted as HTTP POST requests
  *
  * @defgroup postenc HTTP POST encodings
  * See also: https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#form-submission-2
  * @{
  */
 enum MHD_FIXED_ENUM_MHD_APP_SET_ MHD_HTTP_PostEncoding
 {
   /**
    * No post encoding / broken data / unknown encoding
    */
   MHD_HTTP_POST_ENCODING_OTHER = 0
   ,
   /**
    * "application/x-www-form-urlencoded"
    * See https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#url-encoded-form-data
    * See https://url.spec.whatwg.org/#application/x-www-form-urlencoded
    * See https://datatracker.ietf.org/doc/html/rfc3986#section-2
    */
   MHD_HTTP_POST_ENCODING_FORM_URLENCODED = 1
   ,
   /**
    * "multipart/form-data"
    * See https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#multipart-form-data
    * See https://www.rfc-editor.org/rfc/rfc7578.html
    */
   MHD_HTTP_POST_ENCODING_MULTIPART_FORMDATA = 2
   ,
   /**
    * "text/plain"
    * Introduced by HTML5
    * See https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#plain-text-form-data
    * @warning Format is ambiguous. Do not use unless there is a very strong reason.
    */
   MHD_HTTP_POST_ENCODING_TEXT_PLAIN = 3
 };
 
 
 /** @} */ /* end of group postenc */
 
 #define MHD_HTTP_POSTENCODING_DEFINED 1
 #endif /* ! MHD_HTTP_POSTENCODING_DEFINED */
 
 
 /**
  * @brief Standard headers found in HTTP requests and responses.
  *
  * See: https://www.iana.org/assignments/http-fields/http-fields.xhtml
  *
  * @defgroup headers HTTP headers
  * Registry export date: 2023-10-02
  * @{
  */
 
 /* Main HTTP headers. */
 /* Permanent.     RFC9110, Section 12.5.1: HTTP Semantics */
 #define MHD_HTTP_HEADER_ACCEPT       "Accept"
 /* Deprecated.    RFC9110, Section 12.5.2: HTTP Semantics */
 #define MHD_HTTP_HEADER_ACCEPT_CHARSET "Accept-Charset"
 /* Permanent.     RFC9110, Section 12.5.3: HTTP Semantics */
 #define MHD_HTTP_HEADER_ACCEPT_ENCODING "Accept-Encoding"
 /* Permanent.     RFC9110, Section 12.5.4: HTTP Semantics */
 #define MHD_HTTP_HEADER_ACCEPT_LANGUAGE "Accept-Language"
 /* Permanent.     RFC9110, Section 14.3: HTTP Semantics */
 #define MHD_HTTP_HEADER_ACCEPT_RANGES "Accept-Ranges"
 /* Permanent.     RFC9111, Section 5.1: HTTP Caching */
 #define MHD_HTTP_HEADER_AGE          "Age"
 /* Permanent.     RFC9110, Section 10.2.1: HTTP Semantics */
 #define MHD_HTTP_HEADER_ALLOW        "Allow"
 /* Permanent.     RFC9110, Section 11.6.3: HTTP Semantics */
 #define MHD_HTTP_HEADER_AUTHENTICATION_INFO "Authentication-Info"
 /* Permanent.     RFC9110, Section 11.6.2: HTTP Semantics */
 #define MHD_HTTP_HEADER_AUTHORIZATION "Authorization"
 /* Permanent.     RFC9111, Section 5.2 */
 #define MHD_HTTP_HEADER_CACHE_CONTROL "Cache-Control"
 /* Permanent.     RFC9112, Section 9.6: HTTP/1.1 */
 #define MHD_HTTP_HEADER_CLOSE        "Close"
 /* Permanent.     RFC9110, Section 7.6.1: HTTP Semantics */
 #define MHD_HTTP_HEADER_CONNECTION   "Connection"
 /* Permanent.     RFC9110, Section 8.4: HTTP Semantics */
 #define MHD_HTTP_HEADER_CONTENT_ENCODING "Content-Encoding"
 /* Permanent.     RFC9110, Section 8.5: HTTP Semantics */
 #define MHD_HTTP_HEADER_CONTENT_LANGUAGE "Content-Language"
 /* Permanent.     RFC9110, Section 8.6: HTTP Semantics */
 #define MHD_HTTP_HEADER_CONTENT_LENGTH "Content-Length"
 /* Permanent.     RFC9110, Section 8.7: HTTP Semantics */
 #define MHD_HTTP_HEADER_CONTENT_LOCATION "Content-Location"
 /* Permanent.     RFC9110, Section 14.4: HTTP Semantics */
 #define MHD_HTTP_HEADER_CONTENT_RANGE "Content-Range"
 /* Permanent.     RFC9110, Section 8.3: HTTP Semantics */
 #define MHD_HTTP_HEADER_CONTENT_TYPE "Content-Type"
 /* Permanent.     RFC9110, Section 6.6.1: HTTP Semantics */
 #define MHD_HTTP_HEADER_DATE         "Date"
 /* Permanent.     RFC9110, Section 8.8.3: HTTP Semantics */
 #define MHD_HTTP_HEADER_ETAG         "ETag"
 /* Permanent.     RFC9110, Section 10.1.1: HTTP Semantics */
 #define MHD_HTTP_HEADER_EXPECT       "Expect"
 /* Permanent.     RFC9111, Section 5.3: HTTP Caching */
 #define MHD_HTTP_HEADER_EXPIRES      "Expires"
 /* Permanent.     RFC9110, Section 10.1.2: HTTP Semantics */
 #define MHD_HTTP_HEADER_FROM         "From"
 /* Permanent.     RFC9110, Section 7.2: HTTP Semantics */
 #define MHD_HTTP_HEADER_HOST         "Host"
 /* Permanent.     RFC9110, Section 13.1.1: HTTP Semantics */
 #define MHD_HTTP_HEADER_IF_MATCH     "If-Match"
 /* Permanent.     RFC9110, Section 13.1.3: HTTP Semantics */
 #define MHD_HTTP_HEADER_IF_MODIFIED_SINCE "If-Modified-Since"
 /* Permanent.     RFC9110, Section 13.1.2: HTTP Semantics */
 #define MHD_HTTP_HEADER_IF_NONE_MATCH "If-None-Match"
 /* Permanent.     RFC9110, Section 13.1.5: HTTP Semantics */
 #define MHD_HTTP_HEADER_IF_RANGE     "If-Range"
 /* Permanent.     RFC9110, Section 13.1.4: HTTP Semantics */
 #define MHD_HTTP_HEADER_IF_UNMODIFIED_SINCE "If-Unmodified-Since"
 /* Permanent.     RFC9110, Section 8.8.2: HTTP Semantics */
 #define MHD_HTTP_HEADER_LAST_MODIFIED "Last-Modified"
 /* Permanent.     RFC9110, Section 10.2.2: HTTP Semantics */
 #define MHD_HTTP_HEADER_LOCATION     "Location"
 /* Permanent.     RFC9110, Section 7.6.2: HTTP Semantics */
 #define MHD_HTTP_HEADER_MAX_FORWARDS "Max-Forwards"
 /* Permanent.     RFC9112, Appendix B.1: HTTP/1.1 */
 #define MHD_HTTP_HEADER_MIME_VERSION "MIME-Version"
 /* Deprecated.    RFC9111, Section 5.4: HTTP Caching */
 #define MHD_HTTP_HEADER_PRAGMA       "Pragma"
 /* Permanent.     RFC9110, Section 11.7.1: HTTP Semantics */
 #define MHD_HTTP_HEADER_PROXY_AUTHENTICATE "Proxy-Authenticate"
 /* Permanent.     RFC9110, Section 11.7.3: HTTP Semantics */
 #define MHD_HTTP_HEADER_PROXY_AUTHENTICATION_INFO "Proxy-Authentication-Info"
 /* Permanent.     RFC9110, Section 11.7.2: HTTP Semantics */
 #define MHD_HTTP_HEADER_PROXY_AUTHORIZATION "Proxy-Authorization"
 /* Permanent.     RFC9110, Section 14.2: HTTP Semantics */
 #define MHD_HTTP_HEADER_RANGE        "Range"
 /* Permanent.     RFC9110, Section 10.1.3: HTTP Semantics */
 #define MHD_HTTP_HEADER_REFERER      "Referer"
 /* Permanent.     RFC9110, Section 10.2.3: HTTP Semantics */
 #define MHD_HTTP_HEADER_RETRY_AFTER  "Retry-After"
 /* Permanent.     RFC9110, Section 10.2.4: HTTP Semantics */
 #define MHD_HTTP_HEADER_SERVER       "Server"
 /* Permanent.     RFC9110, Section 10.1.4: HTTP Semantics */
 #define MHD_HTTP_HEADER_TE           "TE"
 /* Permanent.     RFC9110, Section 6.6.2: HTTP Semantics */
 #define MHD_HTTP_HEADER_TRAILER      "Trailer"
 /* Permanent.     RFC9112, Section 6.1: HTTP Semantics */
 #define MHD_HTTP_HEADER_TRANSFER_ENCODING "Transfer-Encoding"
 /* Permanent.     RFC9110, Section 7.8: HTTP Semantics */
 #define MHD_HTTP_HEADER_UPGRADE      "Upgrade"
 /* Permanent.     RFC9110, Section 10.1.5: HTTP Semantics */
 #define MHD_HTTP_HEADER_USER_AGENT   "User-Agent"
 /* Permanent.     RFC9110, Section 12.5.5: HTTP Semantics */
 #define MHD_HTTP_HEADER_VARY         "Vary"
 /* Permanent.     RFC9110, Section 7.6.3: HTTP Semantics */
 #define MHD_HTTP_HEADER_VIA          "Via"
 /* Permanent.     RFC9110, Section 11.6.1: HTTP Semantics */
 #define MHD_HTTP_HEADER_WWW_AUTHENTICATE "WWW-Authenticate"
 /* Permanent.     RFC9110, Section 12.5.5: HTTP Semantics */
 #define MHD_HTTP_HEADER_ASTERISK     "*"
 
 /* Additional HTTP headers. */
 /* Permanent.     RFC 3229: Delta encoding in HTTP */
 #define MHD_HTTP_HEADER_A_IM         "A-IM"
 /* Permanent.     RFC 2324: Hyper Text Coffee Pot Control Protocol (HTCPCP/1.0) */
 #define MHD_HTTP_HEADER_ACCEPT_ADDITIONS "Accept-Additions"
 /* Permanent.     RFC 8942, Section 3.1: HTTP Client Hints */
 #define MHD_HTTP_HEADER_ACCEPT_CH    "Accept-CH"
 /* Permanent.     RFC 7089: HTTP Framework for Time-Based Access to Resource States -- Memento */
 #define MHD_HTTP_HEADER_ACCEPT_DATETIME "Accept-Datetime"
 /* Permanent.     RFC 2295: Transparent Content Negotiation in HTTP */
 #define MHD_HTTP_HEADER_ACCEPT_FEATURES "Accept-Features"
 /* Permanent.     RFC 5789: PATCH Method for HTTP */
 #define MHD_HTTP_HEADER_ACCEPT_PATCH "Accept-Patch"
 /* Permanent.     Linked Data Platform 1.0 */
 #define MHD_HTTP_HEADER_ACCEPT_POST  "Accept-Post"
 /* Permanent.     RFC-ietf-httpbis-message-signatures-19, Section 5.1: HTTP Message Signatures */
 #define MHD_HTTP_HEADER_ACCEPT_SIGNATURE "Accept-Signature"
 /* Permanent.     Fetch */
 #define MHD_HTTP_HEADER_ACCESS_CONTROL_ALLOW_CREDENTIALS \
         "Access-Control-Allow-Credentials"
 /* Permanent.     Fetch */
 #define MHD_HTTP_HEADER_ACCESS_CONTROL_ALLOW_HEADERS \
         "Access-Control-Allow-Headers"
 /* Permanent.     Fetch */
 #define MHD_HTTP_HEADER_ACCESS_CONTROL_ALLOW_METHODS \
         "Access-Control-Allow-Methods"
 /* Permanent.     Fetch */
 #define MHD_HTTP_HEADER_ACCESS_CONTROL_ALLOW_ORIGIN \
         "Access-Control-Allow-Origin"
 /* Permanent.     Fetch */
 #define MHD_HTTP_HEADER_ACCESS_CONTROL_EXPOSE_HEADERS \
         "Access-Control-Expose-Headers"
 /* Permanent.     Fetch */
 #define MHD_HTTP_HEADER_ACCESS_CONTROL_MAX_AGE "Access-Control-Max-Age"
 /* Permanent.     Fetch */
 #define MHD_HTTP_HEADER_ACCESS_CONTROL_REQUEST_HEADERS \
         "Access-Control-Request-Headers"
 /* Permanent.     Fetch */
 #define MHD_HTTP_HEADER_ACCESS_CONTROL_REQUEST_METHOD \
         "Access-Control-Request-Method"
 /* Permanent.     RFC 7639, Section 2: The ALPN HTTP Header Field */
 #define MHD_HTTP_HEADER_ALPN         "ALPN"
 /* Permanent.     RFC 7838: HTTP Alternative Services */
 #define MHD_HTTP_HEADER_ALT_SVC      "Alt-Svc"
 /* Permanent.     RFC 7838: HTTP Alternative Services */
 #define MHD_HTTP_HEADER_ALT_USED     "Alt-Used"
 /* Permanent.     RFC 2295: Transparent Content Negotiation in HTTP */
 #define MHD_HTTP_HEADER_ALTERNATES   "Alternates"
 /* Permanent.     RFC 4437: Web Distributed Authoring and Versioning (WebDAV) Redirect Reference Resources */
 #define MHD_HTTP_HEADER_APPLY_TO_REDIRECT_REF "Apply-To-Redirect-Ref"
 /* Permanent.     RFC 8053, Section 4: HTTP Authentication Extensions for Interactive Clients */
 #define MHD_HTTP_HEADER_AUTHENTICATION_CONTROL "Authentication-Control"
 /* Permanent.     RFC9211: The Cache-Status HTTP Response Header Field */
 #define MHD_HTTP_HEADER_CACHE_STATUS "Cache-Status"
 /* Permanent.     RFC 8607, Section 5.1: Calendaring Extensions to WebDAV (CalDAV): Managed Attachments */
 #define MHD_HTTP_HEADER_CAL_MANAGED_ID "Cal-Managed-ID"
 /* Permanent.     RFC 7809, Section 7.1: Calendaring Extensions to WebDAV (CalDAV): Time Zones by Reference */
 #define MHD_HTTP_HEADER_CALDAV_TIMEZONES "CalDAV-Timezones"
 /* Permanent.     RFC9297 */
 #define MHD_HTTP_HEADER_CAPSULE_PROTOCOL "Capsule-Protocol"
 /* Permanent.     RFC9213: Targeted HTTP Cache Control */
 #define MHD_HTTP_HEADER_CDN_CACHE_CONTROL "CDN-Cache-Control"
 /* Permanent.     RFC 8586: Loop Detection in Content Delivery Networks (CDNs) */
 #define MHD_HTTP_HEADER_CDN_LOOP     "CDN-Loop"
 /* Permanent.     RFC 8739, Section 3.3: Support for Short-Term, Automatically Renewed (STAR) Certificates in the Automated Certificate Management Environment (ACME) */
 #define MHD_HTTP_HEADER_CERT_NOT_AFTER "Cert-Not-After"
 /* Permanent.     RFC 8739, Section 3.3: Support for Short-Term, Automatically Renewed (STAR) Certificates in the Automated Certificate Management Environment (ACME) */
 #define MHD_HTTP_HEADER_CERT_NOT_BEFORE "Cert-Not-Before"
 /* Permanent.     Clear Site Data */
 #define MHD_HTTP_HEADER_CLEAR_SITE_DATA "Clear-Site-Data"
 /* Permanent.     RFC9440, Section 2: Client-Cert HTTP Header Field */
 #define MHD_HTTP_HEADER_CLIENT_CERT  "Client-Cert"
 /* Permanent.     RFC9440, Section 2: Client-Cert HTTP Header Field */
 #define MHD_HTTP_HEADER_CLIENT_CERT_CHAIN "Client-Cert-Chain"
 /* Permanent.     RFC-ietf-httpbis-digest-headers-13, Section 2: Digest Fields */
 #define MHD_HTTP_HEADER_CONTENT_DIGEST "Content-Digest"
 /* Permanent.     RFC 6266: Use of the Content-Disposition Header Field in the Hypertext Transfer Protocol (HTTP) */
 #define MHD_HTTP_HEADER_CONTENT_DISPOSITION "Content-Disposition"
 /* Permanent.     The HTTP Distribution and Replication Protocol */
 #define MHD_HTTP_HEADER_CONTENT_ID   "Content-ID"
 /* Permanent.     Content Security Policy Level 3 */
 #define MHD_HTTP_HEADER_CONTENT_SECURITY_POLICY "Content-Security-Policy"
 /* Permanent.     Content Security Policy Level 3 */
 #define MHD_HTTP_HEADER_CONTENT_SECURITY_POLICY_REPORT_ONLY \
         "Content-Security-Policy-Report-Only"
 /* Permanent.     RFC 6265: HTTP State Management Mechanism */
 #define MHD_HTTP_HEADER_COOKIE       "Cookie"
 /* Permanent.     HTML */
 #define MHD_HTTP_HEADER_CROSS_ORIGIN_EMBEDDER_POLICY \
         "Cross-Origin-Embedder-Policy"
 /* Permanent.     HTML */
 #define MHD_HTTP_HEADER_CROSS_ORIGIN_EMBEDDER_POLICY_REPORT_ONLY \
         "Cross-Origin-Embedder-Policy-Report-Only"
 /* Permanent.     HTML */
 #define MHD_HTTP_HEADER_CROSS_ORIGIN_OPENER_POLICY "Cross-Origin-Opener-Policy"
 /* Permanent.     HTML */
 #define MHD_HTTP_HEADER_CROSS_ORIGIN_OPENER_POLICY_REPORT_ONLY \
         "Cross-Origin-Opener-Policy-Report-Only"
 /* Permanent.     Fetch */
 #define MHD_HTTP_HEADER_CROSS_ORIGIN_RESOURCE_POLICY \
         "Cross-Origin-Resource-Policy"
 /* Permanent.     RFC 5323: Web Distributed Authoring and Versioning (WebDAV) SEARCH */
 #define MHD_HTTP_HEADER_DASL         "DASL"
 /* Permanent.     RFC 4918: HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV) */
 #define MHD_HTTP_HEADER_DAV          "DAV"
 /* Permanent.     RFC 3229: Delta encoding in HTTP */
 #define MHD_HTTP_HEADER_DELTA_BASE   "Delta-Base"
 /* Permanent.     RFC 4918: HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV) */
 #define MHD_HTTP_HEADER_DEPTH        "Depth"
 /* Permanent.     RFC 4918: HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV) */
 #define MHD_HTTP_HEADER_DESTINATION  "Destination"
 /* Permanent.     The HTTP Distribution and Replication Protocol */
 #define MHD_HTTP_HEADER_DIFFERENTIAL_ID "Differential-ID"
 /* Permanent.     RFC9449: OAuth 2.0 Demonstrating Proof of Possession (DPoP) */
 #define MHD_HTTP_HEADER_DPOP         "DPoP"
 /* Permanent.     RFC9449: OAuth 2.0 Demonstrating Proof of Possession (DPoP) */
 #define MHD_HTTP_HEADER_DPOP_NONCE   "DPoP-Nonce"
 /* Permanent.     RFC 8470: Using Early Data in HTTP */
 #define MHD_HTTP_HEADER_EARLY_DATA   "Early-Data"
 /* Permanent.     RFC9163: Expect-CT Extension for HTTP */
 #define MHD_HTTP_HEADER_EXPECT_CT    "Expect-CT"
 /* Permanent.     RFC 7239: Forwarded HTTP Extension */
 #define MHD_HTTP_HEADER_FORWARDED    "Forwarded"
 /* Permanent.     RFC 7486, Section 6.1.1: HTTP Origin-Bound Authentication (HOBA) */
 #define MHD_HTTP_HEADER_HOBAREG      "Hobareg"
 /* Permanent.     RFC 4918: HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV) */
 #define MHD_HTTP_HEADER_IF           "If"
 /* Permanent.      RFC 6338: Scheduling Extensions to CalDAV */
 #define MHD_HTTP_HEADER_IF_SCHEDULE_TAG_MATCH "If-Schedule-Tag-Match"
 /* Permanent.     RFC 3229: Delta encoding in HTTP */
 #define MHD_HTTP_HEADER_IM           "IM"
 /* Permanent.     RFC 8473: Token Binding over HTTP */
 #define MHD_HTTP_HEADER_INCLUDE_REFERRED_TOKEN_BINDING_ID \
         "Include-Referred-Token-Binding-ID"
 /* Permanent.     RFC 2068: Hypertext Transfer Protocol -- HTTP/1.1 */
 #define MHD_HTTP_HEADER_KEEP_ALIVE   "Keep-Alive"
 /* Permanent.     RFC 3253: Versioning Extensions to WebDAV: (Web Distributed Authoring and Versioning) */
 #define MHD_HTTP_HEADER_LABEL        "Label"
 /* Permanent.     HTML */
 #define MHD_HTTP_HEADER_LAST_EVENT_ID "Last-Event-ID"
 /* Permanent.     RFC 8288: Web Linking */
 #define MHD_HTTP_HEADER_LINK         "Link"
 /* Permanent.     RFC 4918: HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV) */
 #define MHD_HTTP_HEADER_LOCK_TOKEN   "Lock-Token"
 /* Permanent.     RFC 7089: HTTP Framework for Time-Based Access to Resource States -- Memento */
 #define MHD_HTTP_HEADER_MEMENTO_DATETIME "Memento-Datetime"
 /* Permanent.     RFC 2227: Simple Hit-Metering and Usage-Limiting for HTTP */
 #define MHD_HTTP_HEADER_METER        "Meter"
 /* Permanent.     RFC 2295: Transparent Content Negotiation in HTTP */
 #define MHD_HTTP_HEADER_NEGOTIATE    "Negotiate"
 /* Permanent.     Network Error Logging */
 #define MHD_HTTP_HEADER_NEL          "NEL"
 /* Permanent.     OData Version 4.01 Part 1: Protocol; OASIS; Chet_Ensign */
 #define MHD_HTTP_HEADER_ODATA_ENTITYID "OData-EntityId"
 /* Permanent.     OData Version 4.01 Part 1: Protocol; OASIS; Chet_Ensign */
 #define MHD_HTTP_HEADER_ODATA_ISOLATION "OData-Isolation"
 /* Permanent.     OData Version 4.01 Part 1: Protocol; OASIS; Chet_Ensign */
 #define MHD_HTTP_HEADER_ODATA_MAXVERSION "OData-MaxVersion"
 /* Permanent.     OData Version 4.01 Part 1: Protocol; OASIS; Chet_Ensign */
 #define MHD_HTTP_HEADER_ODATA_VERSION "OData-Version"
 /* Permanent.     RFC 8053, Section 3: HTTP Authentication Extensions for Interactive Clients */
 #define MHD_HTTP_HEADER_OPTIONAL_WWW_AUTHENTICATE "Optional-WWW-Authenticate"
 /* Permanent.     RFC 3648: Web Distributed Authoring and Versioning (WebDAV) Ordered Collections Protocol */
 #define MHD_HTTP_HEADER_ORDERING_TYPE "Ordering-Type"
 /* Permanent.     RFC 6454: The Web Origin Concept */
 #define MHD_HTTP_HEADER_ORIGIN       "Origin"
 /* Permanent.     HTML */
 #define MHD_HTTP_HEADER_ORIGIN_AGENT_CLUSTER "Origin-Agent-Cluster"
 /* Permanent.     RFC 8613, Section 11.1: Object Security for Constrained RESTful Environments (OSCORE) */
 #define MHD_HTTP_HEADER_OSCORE       "OSCORE"
 /* Permanent.     OASIS Project Specification 01; OASIS; Chet_Ensign */
 #define MHD_HTTP_HEADER_OSLC_CORE_VERSION "OSLC-Core-Version"
 /* Permanent.     RFC 4918: HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV) */
 #define MHD_HTTP_HEADER_OVERWRITE    "Overwrite"
 /* Permanent.     HTML */
 #define MHD_HTTP_HEADER_PING_FROM    "Ping-From"
 /* Permanent.     HTML */
 #define MHD_HTTP_HEADER_PING_TO      "Ping-To"
 /* Permanent.     RFC 3648: Web Distributed Authoring and Versioning (WebDAV) Ordered Collections Protocol */
 #define MHD_HTTP_HEADER_POSITION     "Position"
 /* Permanent.     RFC 7240: Prefer Header for HTTP */
 #define MHD_HTTP_HEADER_PREFER       "Prefer"
 /* Permanent.     RFC 7240: Prefer Header for HTTP */
 #define MHD_HTTP_HEADER_PREFERENCE_APPLIED "Preference-Applied"
 /* Permanent.     RFC9218: Extensible Prioritization Scheme for HTTP */
 #define MHD_HTTP_HEADER_PRIORITY     "Priority"
 /* Permanent.     RFC9209: The Proxy-Status HTTP Response Header Field */
 #define MHD_HTTP_HEADER_PROXY_STATUS "Proxy-Status"
 /* Permanent.     RFC 7469: Public Key Pinning Extension for HTTP */
 #define MHD_HTTP_HEADER_PUBLIC_KEY_PINS "Public-Key-Pins"
 /* Permanent.     RFC 7469: Public Key Pinning Extension for HTTP */
 #define MHD_HTTP_HEADER_PUBLIC_KEY_PINS_REPORT_ONLY \
         "Public-Key-Pins-Report-Only"
 /* Permanent.     RFC 4437: Web Distributed Authoring and Versioning (WebDAV) Redirect Reference Resources */
 #define MHD_HTTP_HEADER_REDIRECT_REF "Redirect-Ref"
 /* Permanent.     HTML */
 #define MHD_HTTP_HEADER_REFRESH      "Refresh"
 /* Permanent.     RFC 8555, Section 6.5.1: Automatic Certificate Management Environment (ACME) */
 #define MHD_HTTP_HEADER_REPLAY_NONCE "Replay-Nonce"
 /* Permanent.     RFC-ietf-httpbis-digest-headers-13, Section 3: Digest Fields */
 #define MHD_HTTP_HEADER_REPR_DIGEST  "Repr-Digest"
 /* Permanent.     RFC 6638: Scheduling Extensions to CalDAV */
 #define MHD_HTTP_HEADER_SCHEDULE_REPLY "Schedule-Reply"
 /* Permanent.     RFC 6338: Scheduling Extensions to CalDAV */
 #define MHD_HTTP_HEADER_SCHEDULE_TAG "Schedule-Tag"
 /* Permanent.     Fetch */
 #define MHD_HTTP_HEADER_SEC_PURPOSE  "Sec-Purpose"
 /* Permanent.     RFC 8473: Token Binding over HTTP */
 #define MHD_HTTP_HEADER_SEC_TOKEN_BINDING "Sec-Token-Binding"
 /* Permanent.     RFC 6455: The WebSocket Protocol */
 #define MHD_HTTP_HEADER_SEC_WEBSOCKET_ACCEPT "Sec-WebSocket-Accept"
 /* Permanent.     RFC 6455: The WebSocket Protocol */
 #define MHD_HTTP_HEADER_SEC_WEBSOCKET_EXTENSIONS "Sec-WebSocket-Extensions"
 /* Permanent.     RFC 6455: The WebSocket Protocol */
 #define MHD_HTTP_HEADER_SEC_WEBSOCKET_KEY "Sec-WebSocket-Key"
 /* Permanent.     RFC 6455: The WebSocket Protocol */
 #define MHD_HTTP_HEADER_SEC_WEBSOCKET_PROTOCOL "Sec-WebSocket-Protocol"
 /* Permanent.     RFC 6455: The WebSocket Protocol */
 #define MHD_HTTP_HEADER_SEC_WEBSOCKET_VERSION "Sec-WebSocket-Version"
 /* Permanent.     Server Timing */
 #define MHD_HTTP_HEADER_SERVER_TIMING "Server-Timing"
 /* Permanent.     RFC 6265: HTTP State Management Mechanism */
 #define MHD_HTTP_HEADER_SET_COOKIE   "Set-Cookie"
 /* Permanent.     RFC-ietf-httpbis-message-signatures-19, Section 4.2: HTTP Message Signatures */
 #define MHD_HTTP_HEADER_SIGNATURE    "Signature"
 /* Permanent.     RFC-ietf-httpbis-message-signatures-19, Section 4.1: HTTP Message Signatures */
 #define MHD_HTTP_HEADER_SIGNATURE_INPUT "Signature-Input"
 /* Permanent.     RFC 5023: The Atom Publishing Protocol */
 #define MHD_HTTP_HEADER_SLUG         "SLUG"
 /* Permanent.     Simple Object Access Protocol (SOAP) 1.1 */
 #define MHD_HTTP_HEADER_SOAPACTION   "SoapAction"
 /* Permanent.     RFC 2518: HTTP Extensions for Distributed Authoring -- WEBDAV */
 #define MHD_HTTP_HEADER_STATUS_URI   "Status-URI"
 /* Permanent.     RFC 6797: HTTP Strict Transport Security (HSTS) */
 #define MHD_HTTP_HEADER_STRICT_TRANSPORT_SECURITY "Strict-Transport-Security"
 /* Permanent.     RFC 8594: The Sunset HTTP Header Field */
 #define MHD_HTTP_HEADER_SUNSET       "Sunset"
 /* Permanent.     Edge Architecture Specification */
 #define MHD_HTTP_HEADER_SURROGATE_CAPABILITY "Surrogate-Capability"
 /* Permanent.     Edge Architecture Specification */
 #define MHD_HTTP_HEADER_SURROGATE_CONTROL "Surrogate-Control"
 /* Permanent.     RFC 2295: Transparent Content Negotiation in HTTP */
 #define MHD_HTTP_HEADER_TCN          "TCN"
 /* Permanent.     RFC 4918: HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV) */
 #define MHD_HTTP_HEADER_TIMEOUT      "Timeout"
 /* Permanent.     RFC 8030, Section 5.4: Generic Event Delivery Using HTTP Push */
 #define MHD_HTTP_HEADER_TOPIC        "Topic"
 /* Permanent.     Trace Context */
 #define MHD_HTTP_HEADER_TRACEPARENT  "Traceparent"
 /* Permanent.     Trace Context */
 #define MHD_HTTP_HEADER_TRACESTATE   "Tracestate"
 /* Permanent.     RFC 8030, Section 5.2: Generic Event Delivery Using HTTP Push */
 #define MHD_HTTP_HEADER_TTL          "TTL"
 /* Permanent.     RFC 8030, Section 5.3: Generic Event Delivery Using HTTP Push */
 #define MHD_HTTP_HEADER_URGENCY      "Urgency"
 /* Permanent.     RFC 2295: Transparent Content Negotiation in HTTP */
 #define MHD_HTTP_HEADER_VARIANT_VARY "Variant-Vary"
 /* Permanent.     RFC-ietf-httpbis-digest-headers-13, Section 4: Digest Fields */
 #define MHD_HTTP_HEADER_WANT_CONTENT_DIGEST "Want-Content-Digest"
 /* Permanent.     RFC-ietf-httpbis-digest-headers-13, Section 4: Digest Fields */
 #define MHD_HTTP_HEADER_WANT_REPR_DIGEST "Want-Repr-Digest"
 /* Permanent.     Fetch */
 #define MHD_HTTP_HEADER_X_CONTENT_TYPE_OPTIONS "X-Content-Type-Options"
 /* Permanent.     HTML */
 #define MHD_HTTP_HEADER_X_FRAME_OPTIONS "X-Frame-Options"
 /* Provisional.   AMP-Cache-Transform HTTP request header */
 #define MHD_HTTP_HEADER_AMP_CACHE_TRANSFORM "AMP-Cache-Transform"
 /* Provisional.   OSLC Configuration Management Version 1.0. Part 3: Configuration Specification */
 #define MHD_HTTP_HEADER_CONFIGURATION_CONTEXT "Configuration-Context"
 /* Provisional.   RFC 6017: Electronic Data Interchange - Internet Integration (EDIINT) Features Header Field */
 #define MHD_HTTP_HEADER_EDIINT_FEATURES "EDIINT-Features"
 /* Provisional.   OData Version 4.01 Part 1: Protocol; OASIS; Chet_Ensign */
 #define MHD_HTTP_HEADER_ISOLATION    "Isolation"
 /* Provisional.   Permissions Policy */
 #define MHD_HTTP_HEADER_PERMISSIONS_POLICY "Permissions-Policy"
 /* Provisional.   Repeatable Requests Version 1.0; OASIS; Chet_Ensign */
 #define MHD_HTTP_HEADER_REPEATABILITY_CLIENT_ID "Repeatability-Client-ID"
 /* Provisional.   Repeatable Requests Version 1.0; OASIS; Chet_Ensign */
 #define MHD_HTTP_HEADER_REPEATABILITY_FIRST_SENT "Repeatability-First-Sent"
 /* Provisional.   Repeatable Requests Version 1.0; OASIS; Chet_Ensign */
 #define MHD_HTTP_HEADER_REPEATABILITY_REQUEST_ID "Repeatability-Request-ID"
 /* Provisional.   Repeatable Requests Version 1.0; OASIS; Chet_Ensign */
 #define MHD_HTTP_HEADER_REPEATABILITY_RESULT "Repeatability-Result"
 /* Provisional.   Reporting API */
 #define MHD_HTTP_HEADER_REPORTING_ENDPOINTS "Reporting-Endpoints"
 /* Provisional.   Global Privacy Control (GPC) */
 #define MHD_HTTP_HEADER_SEC_GPC      "Sec-GPC"
 /* Provisional.   Resource Timing Level 1 */
 #define MHD_HTTP_HEADER_TIMING_ALLOW_ORIGIN "Timing-Allow-Origin"
 /* Deprecated.    PEP - an Extension Mechanism for HTTP; status-change-http-experiments-to-historic */
 #define MHD_HTTP_HEADER_C_PEP_INFO   "C-PEP-Info"
 /* Deprecated.    White Paper: Joint Electronic Payment Initiative */
 #define MHD_HTTP_HEADER_PROTOCOL_INFO "Protocol-Info"
 /* Deprecated.    White Paper: Joint Electronic Payment Initiative */
 #define MHD_HTTP_HEADER_PROTOCOL_QUERY "Protocol-Query"
 /* Obsoleted.     Access Control for Cross-site Requests */
 #define MHD_HTTP_HEADER_ACCESS_CONTROL "Access-Control"
 /* Obsoleted.     RFC 2774: An HTTP Extension Framework; status-change-http-experiments-to-historic */
 #define MHD_HTTP_HEADER_C_EXT        "C-Ext"
 /* Obsoleted.     RFC 2774: An HTTP Extension Framework; status-change-http-experiments-to-historic */
 #define MHD_HTTP_HEADER_C_MAN        "C-Man"
 /* Obsoleted.     RFC 2774: An HTTP Extension Framework; status-change-http-experiments-to-historic */
 #define MHD_HTTP_HEADER_C_OPT        "C-Opt"
 /* Obsoleted.     PEP - an Extension Mechanism for HTTP; status-change-http-experiments-to-historic */
 #define MHD_HTTP_HEADER_C_PEP        "C-PEP"
 /* Obsoleted.     RFC 2068: Hypertext Transfer Protocol -- HTTP/1.1; RFC 2616: Hypertext Transfer Protocol -- HTTP/1.1 */
 #define MHD_HTTP_HEADER_CONTENT_BASE "Content-Base"
 /* Obsoleted.     RFC 2616, Section 14.15: Hypertext Transfer Protocol -- HTTP/1.1; RFC 7231, Appendix B: Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content */
 #define MHD_HTTP_HEADER_CONTENT_MD5  "Content-MD5"
 /* Obsoleted.     HTML 4.01 Specification */
 #define MHD_HTTP_HEADER_CONTENT_SCRIPT_TYPE "Content-Script-Type"
 /* Obsoleted.     HTML 4.01 Specification */
 #define MHD_HTTP_HEADER_CONTENT_STYLE_TYPE "Content-Style-Type"
 /* Obsoleted.     RFC 2068: Hypertext Transfer Protocol -- HTTP/1.1 */
 #define MHD_HTTP_HEADER_CONTENT_VERSION "Content-Version"
 /* Obsoleted.     RFC 2965: HTTP State Management Mechanism; RFC 6265: HTTP State Management Mechanism */
 #define MHD_HTTP_HEADER_COOKIE2      "Cookie2"
 /* Obsoleted.     HTML 4.01 Specification */
 #define MHD_HTTP_HEADER_DEFAULT_STYLE "Default-Style"
 /* Obsoleted.     RFC 2068: Hypertext Transfer Protocol -- HTTP/1.1 */
 #define MHD_HTTP_HEADER_DERIVED_FROM "Derived-From"
 /* Obsoleted.     RFC 3230: Instance Digests in HTTP; RFC-ietf-httpbis-digest-headers-13, Section 1.3: Digest Fields */
 #define MHD_HTTP_HEADER_DIGEST       "Digest"
 /* Obsoleted.     RFC 2774: An HTTP Extension Framework; status-change-http-experiments-to-historic */
 #define MHD_HTTP_HEADER_EXT          "Ext"
 /* Obsoleted.     Implementation of OPS Over HTTP */
 #define MHD_HTTP_HEADER_GETPROFILE   "GetProfile"
 /* Obsoleted.     RFC 7540, Section 3.2.1: Hypertext Transfer Protocol Version 2 (HTTP/2) */
 #define MHD_HTTP_HEADER_HTTP2_SETTINGS "HTTP2-Settings"
 /* Obsoleted.     RFC 2774: An HTTP Extension Framework; status-change-http-experiments-to-historic */
 #define MHD_HTTP_HEADER_MAN          "Man"
 /* Obsoleted.     Access Control for Cross-site Requests */
 #define MHD_HTTP_HEADER_METHOD_CHECK "Method-Check"
 /* Obsoleted.     Access Control for Cross-site Requests */
 #define MHD_HTTP_HEADER_METHOD_CHECK_EXPIRES "Method-Check-Expires"
 /* Obsoleted.     RFC 2774: An HTTP Extension Framework; status-change-http-experiments-to-historic */
 #define MHD_HTTP_HEADER_OPT          "Opt"
 /* Obsoleted.     The Platform for Privacy Preferences 1.0 (P3P1.0) Specification */
 #define MHD_HTTP_HEADER_P3P          "P3P"
 /* Obsoleted.     PEP - an Extension Mechanism for HTTP */
 #define MHD_HTTP_HEADER_PEP          "PEP"
 /* Obsoleted.     PEP - an Extension Mechanism for HTTP */
 #define MHD_HTTP_HEADER_PEP_INFO     "Pep-Info"
 /* Obsoleted.     PICS Label Distribution Label Syntax and Communication Protocols */
 #define MHD_HTTP_HEADER_PICS_LABEL   "PICS-Label"
 /* Obsoleted.     Implementation of OPS Over HTTP */
 #define MHD_HTTP_HEADER_PROFILEOBJECT "ProfileObject"
 /* Obsoleted.     PICS Label Distribution Label Syntax and Communication Protocols */
 #define MHD_HTTP_HEADER_PROTOCOL     "Protocol"
 /* Obsoleted.     PICS Label Distribution Label Syntax and Communication Protocols */
 #define MHD_HTTP_HEADER_PROTOCOL_REQUEST "Protocol-Request"
 /* Obsoleted.     Notification for Proxy Caches */
 #define MHD_HTTP_HEADER_PROXY_FEATURES "Proxy-Features"
 /* Obsoleted.     Notification for Proxy Caches */
 #define MHD_HTTP_HEADER_PROXY_INSTRUCTION "Proxy-Instruction"
 /* Obsoleted.     RFC 2068: Hypertext Transfer Protocol -- HTTP/1.1 */
 #define MHD_HTTP_HEADER_PUBLIC       "Public"
 /* Obsoleted.     Access Control for Cross-site Requests */
 #define MHD_HTTP_HEADER_REFERER_ROOT "Referer-Root"
 /* Obsoleted.     RFC 2310: The Safe Response Header Field; status-change-http-experiments-to-historic */
 #define MHD_HTTP_HEADER_SAFE         "Safe"
 /* Obsoleted.     RFC 2660: The Secure HyperText Transfer Protocol; status-change-http-experiments-to-historic */
 #define MHD_HTTP_HEADER_SECURITY_SCHEME "Security-Scheme"
 /* Obsoleted.     RFC 2965: HTTP State Management Mechanism; RFC 6265: HTTP State Management Mechanism */
 #define MHD_HTTP_HEADER_SET_COOKIE2  "Set-Cookie2"
 /* Obsoleted.     Implementation of OPS Over HTTP */
 #define MHD_HTTP_HEADER_SETPROFILE   "SetProfile"
 /* Obsoleted.     RFC 2068: Hypertext Transfer Protocol -- HTTP/1.1 */
 #define MHD_HTTP_HEADER_URI          "URI"
 /* Obsoleted.     RFC 3230: Instance Digests in HTTP; RFC-ietf-httpbis-digest-headers-13, Section 1.3: Digest Fields */
 #define MHD_HTTP_HEADER_WANT_DIGEST  "Want-Digest"
 /* Obsoleted.     RFC9111, Section 5.5: HTTP Caching */
 #define MHD_HTTP_HEADER_WARNING      "Warning"
 
 /* Headers removed from the registry. Do not use! */
 /* Obsoleted.     RFC4229 */
 #define MHD_HTTP_HEADER_COMPLIANCE   "Compliance"
 /* Obsoleted.     RFC4229 */
 #define MHD_HTTP_HEADER_CONTENT_TRANSFER_ENCODING "Content-Transfer-Encoding"
 /* Obsoleted.     RFC4229 */
 #define MHD_HTTP_HEADER_COST         "Cost"
 /* Obsoleted.     RFC4229 */
 #define MHD_HTTP_HEADER_MESSAGE_ID   "Message-ID"
 /* Obsoleted.     RFC4229 */
 #define MHD_HTTP_HEADER_NON_COMPLIANCE "Non-Compliance"
 /* Obsoleted.     RFC4229 */
 #define MHD_HTTP_HEADER_OPTIONAL     "Optional"
 /* Obsoleted.     RFC4229 */
 #define MHD_HTTP_HEADER_RESOLUTION_HINT "Resolution-Hint"
 /* Obsoleted.     RFC4229 */
 #define MHD_HTTP_HEADER_RESOLVER_LOCATION "Resolver-Location"
 /* Obsoleted.     RFC4229 */
 #define MHD_HTTP_HEADER_SUBOK        "SubOK"
 /* Obsoleted.     RFC4229 */
 #define MHD_HTTP_HEADER_SUBST        "Subst"
 /* Obsoleted.     RFC4229 */
 #define MHD_HTTP_HEADER_TITLE        "Title"
 /* Obsoleted.     RFC4229 */
 #define MHD_HTTP_HEADER_UA_COLOR     "UA-Color"
 /* Obsoleted.     RFC4229 */
 #define MHD_HTTP_HEADER_UA_MEDIA     "UA-Media"
 /* Obsoleted.     RFC4229 */
 #define MHD_HTTP_HEADER_UA_PIXELS    "UA-Pixels"
 /* Obsoleted.     RFC4229 */
 #define MHD_HTTP_HEADER_UA_RESOLUTION "UA-Resolution"
 /* Obsoleted.     RFC4229 */
 #define MHD_HTTP_HEADER_UA_WINDOWPIXELS "UA-Windowpixels"
 /* Obsoleted.     RFC4229 */
 #define MHD_HTTP_HEADER_VERSION      "Version"
 /* Obsoleted.     W3C Mobile Web Best Practices Working Group */
 #define MHD_HTTP_HEADER_X_DEVICE_ACCEPT "X-Device-Accept"
 /* Obsoleted.     W3C Mobile Web Best Practices Working Group */
 #define MHD_HTTP_HEADER_X_DEVICE_ACCEPT_CHARSET "X-Device-Accept-Charset"
 /* Obsoleted.     W3C Mobile Web Best Practices Working Group */
 #define MHD_HTTP_HEADER_X_DEVICE_ACCEPT_ENCODING "X-Device-Accept-Encoding"
 /* Obsoleted.     W3C Mobile Web Best Practices Working Group */
 #define MHD_HTTP_HEADER_X_DEVICE_ACCEPT_LANGUAGE "X-Device-Accept-Language"
 /* Obsoleted.     W3C Mobile Web Best Practices Working Group */
 #define MHD_HTTP_HEADER_X_DEVICE_USER_AGENT "X-Device-User-Agent"
 
 
 /**
  * Predefined list of headers
  * To be filled with HPACK static data
  */
 enum MHD_PredefinedHeader
 {
   MHD_PREDEF_ACCEPT_CHARSET = 15,
   MHD_PREDEF_ACCEPT_LANGUAGE = 17
 };
 
 
 /** @} */ /* end of group headers */
 
 /**
  * A client has requested the given url using the given method
  * (#MHD_HTTP_METHOD_GET, #MHD_HTTP_METHOD_PUT,
  * #MHD_HTTP_METHOD_DELETE, #MHD_HTTP_METHOD_POST, etc).
  * If @a upload_size is not zero and response action is provided by this
  * callback, then upload will be discarded and the stream (the connection for
  * HTTP/1.1) will be closed after sending the response.
  *
  * @param cls argument given together with the function
  *        pointer when the handler was registered with MHD
  * @param request the request object
  * @param path the requested uri (without arguments after "?")
  * @param method the HTTP method used (#MHD_HTTP_METHOD_GET,
  *        #MHD_HTTP_METHOD_PUT, etc.)
  * @param upload_size the size of the message upload content payload,
  *                    #MHD_SIZE_UNKNOWN for chunked uploads (if the
  *                    final chunk has not been processed yet)
  * @return action how to proceed, NULL
  *         if the request must be aborted due to a serious
  *         error while handling the request (implies closure
  *         of underling data stream, for HTTP/1.1 it means
  *         socket closure).
  */
 typedef const struct MHD_Action *
 (MHD_FN_PAR_NONNULL_ (2) MHD_FN_PAR_NONNULL_ (3)
  *MHD_RequestCallback)(void *cls,
                        struct MHD_Request *MHD_RESTRICT request,
                        const struct MHD_String *MHD_RESTRICT path,
                        enum MHD_HTTP_Method method,
                        uint_fast64_t upload_size);
 
 
 /**
  * Create (but do not yet start) an MHD daemon.
  * Usually, various options are set before
  * starting the daemon with #MHD_daemon_start().
  *
  * @param req_cb the function to be called for incoming requests
  * @param req_cb_cls the closure for @a cb
  * @return the pointer to the new object on success,
  *         NULL on error (like out-of-memory)
  */
 MHD_EXTERN_ struct MHD_Daemon *
 MHD_daemon_create (MHD_RequestCallback req_cb,
                    void *req_cb_cls)
 MHD_FN_MUST_CHECK_RESULT_;
 
 
 /**
  * Start a webserver.
  * This function:
  * + checks the combination of set options,
  * + initialises the TLS library (if TLS is requested),
  * + creates the listen socket (if not provided and if allowed),
  * + starts the daemon internal threads (if allowed)
  *
  * @param[in,out] daemon daemon to start; you can no longer set
  *        options on this daemon after this call!
  * @return #MHD_SC_OK on success
  * @ingroup daemon
  */
 MHD_EXTERN_ enum MHD_StatusCode
 MHD_daemon_start (struct MHD_Daemon *daemon)
 MHD_FN_PAR_NONNULL_ (1) MHD_FN_MUST_CHECK_RESULT_;
 
 
 /**
  * Stop accepting connections from the listening socket.  Allows
  * clients to continue processing, but stops accepting new
  * connections.  Note that the caller is responsible for closing the
  * returned socket; however, if MHD is run using threads (anything but
  * external select mode), it must not be closed until AFTER
  * #MHD_daemon_destroy() has been called (as it is theoretically possible
  * that an existing thread is still using it).
  *
  * @param[in,out] daemon the daemon to stop accepting new connections for
  * @return the old listen socket on success, #MHD_INVALID_SOCKET if
  *         the daemon was already not listening anymore, or
  *         was never started, or has no listen socket.
  * @ingroup daemon
  */
 MHD_EXTERN_ MHD_Socket
 MHD_daemon_quiesce (struct MHD_Daemon *daemon)
 MHD_FN_PAR_NONNULL_ALL_ MHD_FN_PAR_INOUT_ (1);
 
 
 /**
  * Shutdown and destroy an HTTP daemon.
  *
  * @param[in] daemon daemon to stop
  * @ingroup daemon
  */
 MHD_EXTERN_ void
 MHD_daemon_destroy (struct MHD_Daemon *daemon)
 MHD_FN_PAR_NONNULL_ALL_;
 
 /* ******************* External event loop ************************ */
 
 /**
  * @defgroup event External network events processing
  */
 
 /**
  * The network status of the socket.
  * When set by MHD (by #MHD_SocketRegistrationUpdateCallback or
  * similar) it indicates a request to watch for specific socket state:
  * watch for readiness for receiving the data, watch for readiness for sending
  * the data and/or watch for exception state of the socket.
  * When set by application (and provided for #MHD_daemon_event_update() and
  * similar) it must indicate the actual status of the socket.
  *
  * Any actual state is a bitwise OR combination of #MHD_FD_STATE_RECV,
  * #MHD_FD_STATE_SEND, #MHD_FD_STATE_EXCEPT.
  * @ingroup event
  */
 enum MHD_FIXED_ENUM_ MHD_FdState
 {
   /**
    * The socket is not ready for receiving or sending and
    * does not have any exceptional state.
    * The state never set by MHD, except de-registration of the sockets
    * in a #MHD_SocketRegistrationUpdateCallback.
    */
   MHD_FD_STATE_NONE = 0
   ,
   /* ** Three bit-flags ** */
 
   /**
    * Indicates that socket should be watched for incoming data
    * (when set by #MHD_SocketRegistrationUpdateCallback)
    * / socket has incoming data ready to read (when used for
    * #MHD_daemon_event_update())
    */
   MHD_FD_STATE_RECV = 1 << 0
   ,
   /**
    * Indicates that socket should be watched for availability for sending
    * (when set by #MHD_SocketRegistrationUpdateCallback)
    * / socket has ability to send data (when used for
    * #MHD_daemon_event_update())
    */
   MHD_FD_STATE_SEND = 1 << 1
   ,
   /**
    * Indicates that socket should be watched for disconnect, out-of-band
    * data available or high priority data available (when set by
    * #MHD_SocketRegistrationUpdateCallback)
    * / socket has been disconnected, has out-of-band data available or
    * has high priority data available (when used for
    * #MHD_daemon_event_update()). This status must not include "remote
    * peer shut down writing" status.
    * Note: #MHD_SocketRegistrationUpdateCallback() always set it as exceptions
    * must be always watched.
    */
   MHD_FD_STATE_EXCEPT = 1 << 2
   ,
 
   /* The rest of the list is a bit-wise combination of three main
    * states. Application may use three main states directly as
    * a bit-mask instead of using of the following values
    */
 
   /**
    * Combination of #MHD_FD_STATE_RECV and #MHD_FD_STATE_SEND states.
    */
   MHD_FD_STATE_RECV_SEND = MHD_FD_STATE_RECV | MHD_FD_STATE_SEND
   ,
   /**
    * Combination of #MHD_FD_STATE_RECV and #MHD_FD_STATE_EXCEPT states.
    */
   MHD_FD_STATE_RECV_EXCEPT = MHD_FD_STATE_RECV | MHD_FD_STATE_EXCEPT
   ,
   /**
    * Combination of #MHD_FD_STATE_RECV and #MHD_FD_STATE_EXCEPT states.
    */
   MHD_FD_STATE_SEND_EXCEPT = MHD_FD_STATE_RECV | MHD_FD_STATE_EXCEPT
   ,
   /**
    * Combination of #MHD_FD_STATE_RECV, #MHD_FD_STATE_SEND and
    * #MHD_FD_STATE_EXCEPT states.
    */
   MHD_FD_STATE_RECV_SEND_EXCEPT = \
     MHD_FD_STATE_RECV | MHD_FD_STATE_SEND | MHD_FD_STATE_EXCEPT
 };
 
 /**
  * Checks whether specific @a state is enabled/set in the @a var
  */
 #define MHD_FD_STATE_IS_SET(var,state)               \
         (MHD_FD_STATE_NONE !=                        \
          ((enum MHD_FdState) (((unsigned int) (var)) \
                               & ((unsigned int) (state)))))
 
 /**
  * Checks whether RECV is enabled/set in the @a var
  */
 #define MHD_FD_STATE_IS_SET_RECV(var) \
         MHD_FD_STATE_IS_SET ((var),MHD_FD_STATE_RECV)
 /**
  * Checks whether SEND is enabled/set in the @a var
  */
 #define MHD_FD_STATE_IS_SET_SEND(var) \
         MHD_FD_STATE_IS_SET ((var),MHD_FD_STATE_SEND)
 /**
  * Checks whether EXCEPT is enabled/set in the @a var
  */
 #define MHD_FD_STATE_IS_SET_EXCEPT(var) \
         MHD_FD_STATE_IS_SET ((var),MHD_FD_STATE_EXCEPT)
 
 
 /**
  * Set/enable specific @a state in the @a var
  */
 #define MHD_FD_STATE_SET(var,state) \
         ((var) =                    \
            (enum MHD_FdState) (((unsigned int) var) | ((unsigned int) state)))
 /**
  * Set/enable RECV state in the @a var
  */
 #define MHD_FD_STATE_SET_RECV(var) MHD_FD_STATE_SET ((var),MHD_FD_STATE_RECV)
 /**
  * Set/enable SEND state in the @a var
  */
 #define MHD_FD_STATE_SET_SEND(var) MHD_FD_STATE_SET ((var),MHD_FD_STATE_SEND)
 /**
  * Set/enable EXCEPT state in the @a var
  */
 #define MHD_FD_STATE_SET_EXCEPT(var) \
         MHD_FD_STATE_SET ((var),MHD_FD_STATE_EXCEPT)
 
 /**
  * Clear/disable specific @a state in the @a var
  */
 #define MHD_FD_STATE_CLEAR(var,state) \
         ( (var) =                     \
             (enum MHD_FdState)        \
             (((unsigned int) var)     \
              & ((enum MHD_FdState) (~((unsigned int) state)))) \
         )
 /**
  * Clear/disable RECV state in the @a var
  */
 #define MHD_FD_STATE_CLEAR_RECV(var) \
         MHD_FD_STATE_CLEAR ((var),MHD_FD_STATE_RECV)
 /**
  * Clear/disable SEND state in the @a var
  */
 #define MHD_FD_STATE_CLEAR_SEND(var) \
         MHD_FD_STATE_CLEAR ((var),MHD_FD_STATE_SEND)
 /**
  * Clear/disable EXCEPT state in the @a var
  */
 #define MHD_FD_STATE_CLEAR_EXCEPT(var) \
         MHD_FD_STATE_CLEAR ((var),MHD_FD_STATE_EXCEPT)
 
 
 /**
  * The context data to be used for updates of the socket state
  */
 struct MHD_EventUpdateContext;
 
 
 /* Define MHD_APP_SOCKET_CNTX_TYPE to the socket context type before
  * including this header.
  * This is optional, but improves the types safety.
  * For example:
  * #define MHD_APP_SOCKET_CNTX_TYPE struct my_structure
  */
 #ifndef MHD_APP_SOCKET_CNTX_TYPE
 #  define MHD_APP_SOCKET_CNTX_TYPE void
 #endif
 
 /**
  * The callback for registration/de-registration of the sockets to watch.
  *
  * This callback must not call #MHD_daemon_destroy(), #MHD_daemon_quiesce(),
  * #MHD_daemon_add_connection().
  *
  * @param cls the closure
  * @param fd the socket to watch
  * @param watch_for the states of the @a fd to watch, if set to
  *                  #MHD_FD_STATE_NONE the socket must be de-registred
  * @param app_cntx_old the old application defined context for the socket,
  *                     NULL if @a fd socket was not registered before
  * @param ecb_cntx the context handle to be used
  *                 with #MHD_daemon_event_update()
  * @return must be NULL for the removed (de-registred) sockets,
  *         for new and updated sockets: NULL in case of error (the connection
  *         will be aborted or daemon failed to start if FD does not belong to
  *         connection)
  *         or the new socket context (opaque for MHD, must be non-NULL)
  * @sa #MHD_D_OPTION_REREGISTER_ALL
  * @ingroup event
  */
 typedef MHD_APP_SOCKET_CNTX_TYPE *
 (MHD_FN_PAR_NONNULL_ (5)
  *MHD_SocketRegistrationUpdateCallback)(
   void *cls,
   MHD_Socket fd,
   enum MHD_FdState watch_for,
   MHD_APP_SOCKET_CNTX_TYPE *app_cntx_old,
   struct MHD_EventUpdateContext *ecb_cntx);
 
 
 /**
  * Update the sockets state.
  * Must be called for every socket that got state updated.
  * For #MHD_D_OPTION_WM_EXTERNAL_EVENT_LOOP_CB_LEVEL() mode
  * this function must be called for each socket between any two calls of
  * #MHD_daemon_process_reg_events() function.
  * Available only for daemons started in
  * #MHD_D_OPTION_WM_EXTERNAL_EVENT_LOOP_CB_LEVEL or
  * #MHD_D_OPTION_WM_EXTERNAL_EVENT_LOOP_CB_EDGE modes.
  * @param daemon the daemon handle
  * @param ecb_cntx the context handle provided
  *                 for #MHD_SocketRegistrationUpdateCallback
  * @param fd_current_state the current state of the socket
  * @ingroup event
  */
 MHD_EXTERN_ void
 MHD_daemon_event_update (
   struct MHD_Daemon *MHD_RESTRICT daemon,
   struct MHD_EventUpdateContext *MHD_RESTRICT ecb_cntx,
   enum MHD_FdState fd_current_state)
 MHD_FN_PAR_NONNULL_ (1) MHD_FN_PAR_NONNULL_ (2);
 
 
 /**
  * Perform all daemon activities based on FDs events provided earlier by
  * application via #MHD_daemon_event_update().
  *
  * This function accepts new connections (if any), performs HTTP communications
  * on all active connections, closes connections as needed and performs FDs
  * registration updates by calling #MHD_SocketRegistrationUpdateCallback
  * callback for every socket that needs to be added/updated/removed.
  *
  * Available only for daemons started in #MHD_WM_EXTERNAL_EVENT_LOOP_CB_LEVEL or
  * #MHD_WM_EXTERNAL_EVENT_LOOP_CB_EDGE modes.
  *
  * When used in #MHD_WM_EXTERNAL_EVENT_LOOP_CB_LEVEL mode, application must
  * provide all updates by calling #MHD_daemon_event_update() for every
  * registered FD between any two calls of this function.
  *
  * @param daemon the daemon handle
  * @param[out] next_max_wait_milsec the optional pointer to receive the
                                     next maximum wait time in milliseconds
                                     to be used for the sockets polling
                                     function, can be NULL
  * @return #MHD_SC_OK on success,
  *         error code otherwise
  * @sa #MHD_D_OPTION_REREGISTER_ALL
  * @ingroup event
  */
 MHD_EXTERN_ enum MHD_StatusCode
 MHD_daemon_process_reg_events (
   struct MHD_Daemon *MHD_RESTRICT daemon,
   uint_fast64_t *MHD_RESTRICT next_max_wait_milsec)
 MHD_FN_PAR_NONNULL_ (1);
 
 /* ********************* daemon options ************** */
 
 
 /**
  * Which threading and polling mode should be used by MHD?
  */
 enum MHD_FIXED_ENUM_APP_SET_ MHD_WorkMode
 {
   /**
    * Work mode with no internal threads.
    * The application periodically calls #MHD_daemon_process_blocking(), where
    * MHD internally checks all sockets automatically.
    * This is the default mode.
    * Use helper macro #MHD_D_OPTION_WM_EXTERNAL_PERIODIC() to enable
    * this mode.
    */
   MHD_WM_EXTERNAL_PERIODIC = 0
   ,
   /**
    * Work mode with an external event loop with level triggers.
    * MHD provides registration of all FDs to be monitored by using
    * #MHD_SocketRegistrationUpdateCallback, application performs level triggered
    * FDs polling (like select() or poll()), calls function
    * #MHD_daemon_event_update() for every registered FD and then calls main
    * function MHD_daemon_process_reg_events() to process the data.
    * Use helper macro #MHD_D_OPTION_WM_EXTERNAL_EVENT_LOOP_CB_LEVEL() to enable
    * this mode.
    * @sa #MHD_D_OPTION_REREGISTER_ALL
    */
   MHD_WM_EXTERNAL_EVENT_LOOP_CB_LEVEL = 8
   ,
   /**
    * Work mode with an external event loop with edge triggers.
    * MHD provides registration of all FDs to be monitored by using
    * #MHD_SocketRegistrationUpdateCallback, application performs edge triggered
    * sockets polling (like epoll with EPOLLET), calls function
    * #MHD_daemon_event_update() for FDs with updated states and then calls main
    * function MHD_daemon_process_reg_events() to process the data.
    * Use helper macro #MHD_D_OPTION_WM_EXTERNAL_EVENT_LOOP_CB_EDGE() to enable
    * this mode.
    * @sa #MHD_D_OPTION_REREGISTER_ALL
    */
   MHD_WM_EXTERNAL_EVENT_LOOP_CB_EDGE = 9
   ,
   /**
    * Work mode with no internal threads and aggregate watch FD.
    * Application uses #MHD_DAEMON_INFO_FIXED_AGGREAGATE_FD to get single FD
    * that gets triggered by any MHD event.
    * This FD can be watched as an aggregate indicator for all MHD events.
    * This mode is available only on selected platforms (currently
    * GNU/Linux and OpenIndiana only), see #MHD_LIB_INFO_FIXED_HAS_AGGREGATE_FD.
    * When the FD is triggered, #MHD_daemon_process_nonblocking() should
    * be called.
    * Use helper macro #MHD_D_OPTION_WM_EXTERNAL_SINGLE_FD_WATCH() to enable
    * this mode.
    */
   MHD_WM_EXTERNAL_SINGLE_FD_WATCH = 16
   ,
   /**
    * Work mode with one or more worker threads.
    * If specified number of threads is one, then daemon starts with single
    * worker thread that handles all connections.
    * If number of threads is larger than one, then that number of worker
    * threads, and handling of connection is distributed among the workers.
    * Use helper macro #MHD_D_OPTION_WM_WORKER_THREADS() to enable
    * this mode.
    */
   MHD_WM_WORKER_THREADS = 24
   ,
   /**
    * Work mode with one internal thread for listening and additional threads
    * per every connection.  Use this if handling requests is CPU-intensive or
    * blocking, your application is thread-safe and you have plenty of
    * memory (per connection).
    * Use helper macro #MHD_D_OPTION_WM_THREAD_PER_CONNECTION() to enable
    * this mode.
    */
   MHD_WM_THREAD_PER_CONNECTION = 32
 };
 
 /**
  * Work mode parameters for #MHD_WM_EXTERNAL_EVENT_LOOP_CB_LEVEL and
  * #MHD_WM_EXTERNAL_EVENT_LOOP_CB_EDGE modes
  */
 struct MHD_WorkModeExternalEventLoopCBParam
 {
   /**
    * Socket registration callback
    */
   MHD_SocketRegistrationUpdateCallback reg_cb;
   /**
    * Closure for the @a reg_cb
    */
   void *reg_cb_cls;
 };
 
 /**
  * MHD work mode parameters
  */
 union MHD_WorkModeParam
 {
   /**
    * Work mode parameters for #MHD_WM_EXTERNAL_EVENT_LOOP_CB_LEVEL and
    * #MHD_WM_EXTERNAL_EVENT_LOOP_CB_EDGE modes
    */
   struct MHD_WorkModeExternalEventLoopCBParam v_external_event_loop_cb;
   /**
    * Number of worker threads for #MHD_WM_WORKER_THREADS.
    * If set to one, then daemon starts with single worker thread that process
    * all connections.
    * If set to value larger than one, then that number of worker threads
    * and distributed handling of requests among the workers.
    * Zero is treated as one.
    */
   unsigned int num_worker_threads;
 };
 
 /**
  * Parameter for #MHD_D_O_WORK_MODE().
  * Not recommended to be used directly, better use macro/functions to create it:
  * #MHD_WM_OPTION_EXTERNAL_PERIODIC(),
  * #MHD_WM_OPTION_EXTERNAL_EVENT_LOOP_CB_LEVEL(),
  * #MHD_WM_OPTION_EXTERNAL_EVENT_LOOP_CB_EDGE(),
  * #MHD_WM_OPTION_EXTERNAL_SINGLE_FD_WATCH(),
  * #MHD_WM_OPTION_WORKER_THREADS(),
  * #MHD_WM_OPTION_THREAD_PER_CONNECTION()
  */
 struct MHD_WorkModeWithParam
 {
   /**
    * The work mode for MHD
    */
   enum MHD_WorkMode mode;
   /**
    * The parameters used for specified work mode
    */
   union MHD_WorkModeParam params;
 };
 
 
 #if defined(MHD_USE_COMPOUND_LITERALS) && defined(MHD_USE_DESIG_NEST_INIT)
 /**
  * Create parameter for #MHD_D_O_WORK_MODE() for work mode with
  * no internal threads.
  * The application periodically calls #MHD_daemon_process_blocking(), where
  * MHD internally checks all sockets automatically.
  * This is the default mode.
  * @return the object of struct MHD_WorkModeWithParam with requested values
  */
 #  define MHD_WM_OPTION_EXTERNAL_PERIODIC()     \
         MHD_NOWARN_COMPOUND_LITERALS_                 \
           (const struct MHD_WorkModeWithParam)          \
         {                                             \
           .mode = (MHD_WM_EXTERNAL_PERIODIC)          \
         }                                             \
         MHD_RESTORE_WARN_COMPOUND_LITERALS_
 
 /**
  * Create parameter for #MHD_D_O_WORK_MODE() for work mode with
  * an external event loop with level triggers.
  * Application uses #MHD_SocketRegistrationUpdateCallback, level triggered
  * sockets polling (like select() or poll()) and #MHD_daemon_event_update().
  * @param cb_val the callback for sockets registration
  * @param cb_cls_val the closure for the @a cv_val callback
  * @return the object of struct MHD_WorkModeWithParam with requested values
  */
 #  define MHD_WM_OPTION_EXTERNAL_EVENT_LOOP_CB_LEVEL(cb_val,cb_cls_val) \
         MHD_NOWARN_COMPOUND_LITERALS_                                         \
           (const struct MHD_WorkModeWithParam)                                  \
         {                                                                     \
           .mode = (MHD_WM_EXTERNAL_EVENT_LOOP_CB_LEVEL),                      \
           .params.v_external_event_loop_cb.reg_cb = (cb_val),                 \
           .params.v_external_event_loop_cb.reg_cb_cls = (cb_cls_val)          \
         }                                                                     \
         MHD_RESTORE_WARN_COMPOUND_LITERALS_
 
 /**
  * Create parameter for #MHD_D_O_WORK_MODE() for work mode with
  * an external event loop with edge triggers.
  * Application uses #MHD_SocketRegistrationUpdateCallback, edge triggered
  * sockets polling (like epoll with EPOLLET) and #MHD_daemon_event_update().
  * @param cb_val the callback for sockets registration
  * @param cb_cls_val the closure for the @a cv_val callback
  * @return the object of struct MHD_WorkModeWithParam with requested values
  */
 #  define MHD_WM_OPTION_EXTERNAL_EVENT_LOOP_CB_EDGE(cb_val,cb_cls_val)  \
         MHD_NOWARN_COMPOUND_LITERALS_                                         \
           (const struct MHD_WorkModeWithParam)                                  \
         {                                                                     \
           .mode = (MHD_WM_EXTERNAL_EVENT_LOOP_CB_EDGE),                       \
           .params.v_external_event_loop_cb.reg_cb = (cb_val),                 \
           .params.v_external_event_loop_cb.reg_cb_cls = (cb_cls_val)          \
         }                                                                     \
         MHD_RESTORE_WARN_COMPOUND_LITERALS_
 
 /**
  * Create parameter for #MHD_D_O_WORK_MODE() for work mode with
  * no internal threads and aggregate watch FD.
  * Application uses #MHD_DAEMON_INFO_FIXED_AGGREAGATE_FD to get single FD
  * that gets triggered by any MHD event.
  * This FD can be watched as an aggregate indicator for all MHD events.
  * This mode is available only on selected platforms (currently
  * GNU/Linux only), see #MHD_LIB_INFO_FIXED_HAS_AGGREGATE_FD.
  * When the FD is triggered, #MHD_daemon_process_nonblocking() should
  * be called.
  * @return the object of struct MHD_WorkModeWithParam with requested values
  */
 #  define MHD_WM_OPTION_EXTERNAL_SINGLE_FD_WATCH()      \
         MHD_NOWARN_COMPOUND_LITERALS_                         \
           (const struct MHD_WorkModeWithParam)                  \
         {                                                     \
           .mode = (MHD_WM_EXTERNAL_SINGLE_FD_WATCH)           \
         }                                                     \
         MHD_RESTORE_WARN_COMPOUND_LITERALS_
 
 /**
  * Create parameter for #MHD_D_O_WORK_MODE() for work mode with
  * one or more worker threads.
  * If number of threads is one, then daemon starts with single worker thread
  * that handles all connections.
  * If number of threads is larger than one, then that number of worker threads,
  * and handling of connection is distributed among the workers.
  * @param num_workers the number of worker threads, zero is treated as one
  * @return the object of struct MHD_WorkModeWithParam with requested values
  */
 #  define MHD_WM_OPTION_WORKER_THREADS(num_workers)     \
         MHD_NOWARN_COMPOUND_LITERALS_                         \
           (const struct MHD_WorkModeWithParam)                  \
         {                                                     \
           .mode = (MHD_WM_WORKER_THREADS),                    \
           .params.num_worker_threads = (num_workers)          \
         }                                                     \
         MHD_RESTORE_WARN_COMPOUND_LITERALS_
 
 /**
  * Create parameter for #MHD_D_O_WORK_MODE() for work mode with
  * one internal thread for listening and additional threads per every
  * connection.  Use this if handling requests is CPU-intensive or blocking,
  * your application is thread-safe and you have plenty of memory (per
  * connection).
  * @return the object of struct MHD_WorkModeWithParam with requested values
  */
 #  define MHD_WM_OPTION_THREAD_PER_CONNECTION() \
         MHD_NOWARN_COMPOUND_LITERALS_                 \
           (const struct MHD_WorkModeWithParam)          \
         {                                             \
           .mode = (MHD_WM_THREAD_PER_CONNECTION)      \
         }                                             \
         MHD_RESTORE_WARN_COMPOUND_LITERALS_
 
 #else  /* !MHD_USE_COMPOUND_LITERALS || !MHD_USE_DESIG_NEST_INIT */
 MHD_NOWARN_UNUSED_FUNC_
 
 /**
  * Create parameter for #MHD_D_O_WORK_MODE() for work mode with
  * no internal threads.
  * The application periodically calls #MHD_daemon_process_blocking(), where
  * MHD internally checks all sockets automatically.
  * This is the default mode.
  * @return the object of struct MHD_WorkModeWithParam with requested values
  */
 static MHD_INLINE struct MHD_WorkModeWithParam
 MHD_WM_OPTION_EXTERNAL_PERIODIC (void)
 {
   struct MHD_WorkModeWithParam wm_val;
 
   wm_val.mode = MHD_WM_EXTERNAL_PERIODIC;
 
   return wm_val;
 }
 
 
 /**
  * Create parameter for #MHD_D_O_WORK_MODE() for work mode with
  * an external event loop with level triggers.
  * Application uses #MHD_SocketRegistrationUpdateCallback, level triggered
  * sockets polling (like select() or poll()) and #MHD_daemon_event_update().
  * @param cb_val the callback for sockets registration
  * @param cb_cls_val the closure for the @a cv_val callback
  * @return the object of struct MHD_WorkModeWithParam with requested values
  */
 static MHD_INLINE struct MHD_WorkModeWithParam
 MHD_WM_OPTION_EXTERNAL_EVENT_LOOP_CB_LEVEL (
   MHD_SocketRegistrationUpdateCallback cb_val,
   void *cb_cls_val)
 {
   struct MHD_WorkModeWithParam wm_val;
 
   wm_val.mode = MHD_WM_EXTERNAL_EVENT_LOOP_CB_LEVEL;
   wm_val.params.v_external_event_loop_cb.reg_cb = cb_val;
   wm_val.params.v_external_event_loop_cb.reg_cb_cls = cb_cls_val;
 
   return wm_val;
 }
 
 
 /**
  * Create parameter for #MHD_D_O_WORK_MODE() for work mode with
  * an external event loop with edge triggers.
  * Application uses #MHD_SocketRegistrationUpdateCallback, edge triggered
  * sockets polling (like epoll with EPOLLET) and #MHD_daemon_event_update().
  * @param cb_val the callback for sockets registration
  * @param cb_cls_val the closure for the @a cv_val callback
  * @return the object of struct MHD_WorkModeWithParam with requested values
  */
 static MHD_INLINE struct MHD_WorkModeWithParam
 MHD_WM_OPTION_EXTERNAL_EVENT_LOOP_CB_EDGE (
   MHD_SocketRegistrationUpdateCallback cb_val,
   void *cb_cls_val)
 {
   struct MHD_WorkModeWithParam wm_val;
 
   wm_val.mode = MHD_WM_EXTERNAL_EVENT_LOOP_CB_EDGE;
   wm_val.params.v_external_event_loop_cb.reg_cb = cb_val;
   wm_val.params.v_external_event_loop_cb.reg_cb_cls = cb_cls_val;
 
   return wm_val;
 }
 
 
 /**
  * Create parameter for #MHD_D_O_WORK_MODE() for work mode with
  * no internal threads and aggregate watch FD.
  * Application uses #MHD_DAEMON_INFO_FIXED_AGGREAGATE_FD to get single FD
  * that gets triggered by any MHD event.
  * This FD can be watched as an aggregate indicator for all MHD events.
  * This mode is available only on selected platforms (currently
  * GNU/Linux only), see #MHD_LIB_INFO_FIXED_HAS_AGGREGATE_FD.
  * When the FD is triggered, #MHD_daemon_process_nonblocking() should
  * be called.
  * @return the object of struct MHD_WorkModeWithParam with requested values
  */
 static MHD_INLINE struct MHD_WorkModeWithParam
 MHD_WM_OPTION_EXTERNAL_SINGLE_FD_WATCH (void)
 {
   struct MHD_WorkModeWithParam wm_val;
 
   wm_val.mode = MHD_WM_EXTERNAL_SINGLE_FD_WATCH;
 
   return wm_val;
 }
 
 
 /**
  * Create parameter for #MHD_D_O_WORK_MODE() for work mode with
  * one or more worker threads.
  * If number of threads is one, then daemon starts with single worker thread
  * that handles all connections.
  * If number of threads is larger than one, then that number of worker threads,
  * and handling of connection is distributed among the workers.
  * @param num_workers the number of worker threads, zero is treated as one
  * @return the object of struct MHD_WorkModeWithParam with requested values
  */
 static MHD_INLINE struct MHD_WorkModeWithParam
 MHD_WM_OPTION_WORKER_THREADS (unsigned int num_workers)
 {
   struct MHD_WorkModeWithParam wm_val;
 
   wm_val.mode = MHD_WM_EXTERNAL_EVENT_LOOP_CB_EDGE;
   wm_val.params.num_worker_threads = num_workers;
 
   return wm_val;
 }
 
 
 /**
  * Create parameter for #MHD_D_O_WORK_MODE() for work mode with
  * one internal thread for listening and additional threads per every
  * connection.  Use this if handling requests is CPU-intensive or blocking,
  * your application is thread-safe and you have plenty of memory (per
  * connection).
  * @return the object of struct MHD_WorkModeWithParam with requested values
  */
 static MHD_INLINE struct MHD_WorkModeWithParam
 MHD_WM_OPTION_THREAD_PER_CONNECTION (void)
 {
   struct MHD_WorkModeWithParam wm_val;
 
   wm_val.mode = MHD_WM_THREAD_PER_CONNECTION;
 
   return wm_val;
 }
 
 
 MHD_RESTORE_WARN_UNUSED_FUNC_
 #endif /* !MHD_USE_COMPOUND_LITERALS || !MHD_USE_DESIG_NEST_INIT */
 
 /**
  * @defgroup logging Log events and control
  */
 
 
 /**
  * Type of a callback function used for logging by MHD.
  *
  * @param cls closure
  * @param sc status code of the event
  * @param fm format string (`printf()`-style)
  * @param ap arguments to @a fm
  * @ingroup logging
  */
 typedef void
 (MHD_FN_PAR_NONNULL_ (3)
  MHD_FN_PAR_CSTR_ (3)
  *MHD_LoggingCallback)(void *cls,
                        enum MHD_StatusCode sc,
                        const char *fm,
                        va_list ap);
 
 /**
  * Parameter for listen socket binding type
  */
 enum MHD_FIXED_ENUM_APP_SET_ MHD_DaemonOptionBindType
 {
   /**
    * The listen socket bind to the networks address with sharing the address.
    * Several sockets can bind to the same address.
    */
   MHD_D_OPTION_BIND_TYPE_SHARED = -1
   ,
   /**
    * The listen socket bind to the networks address without sharing the address,
    * except allowing binding to port/address which has TIME_WAIT state (the
    * state after closing connection).
    * On some platforms it may also allow to bind to specific address if other
    * socket already bond to the same port of wildcard address (or bind to
    * wildcard address when other socket already bond to specific address
    * with the same port).
    * Typically achieved by enabling 'SO_REUSEADDR' socket option.
    * Default.
    */
   MHD_D_OPTION_BIND_TYPE_NOT_SHARED = 0
   ,
   /**
    * The listen socket bind to the networks address without sharing the address.
    * The daemon way fail to start when any sockets still in "TIME_WAIT" state
    * on the same port, which effectively prevents quick restart of the daemon
    * on the same port.
    * On W32 systems it works like #MHD_D_OPTION_BIND_TYPE_NOT_SHARED due to
    * the OS limitations.
    */
   MHD_D_OPTION_BIND_TYPE_NOT_SHARED_STRICTER = 1
   ,
   /**
    * The list socket bind to the networks address in explicit exclusive mode.
    * Works as #MHD_D_OPTION_BIND_TYPE_NOT_SHARED_STRICTER on platforms without
    * support for the explicit exclusive socket use.
    */
   MHD_D_OPTION_BIND_TYPE_EXCLUSIVE = 2
 };
 
 
 /**
  * Possible levels of enforcement for TCP_FASTOPEN.
  */
 enum MHD_FIXED_ENUM_APP_SET_ MHD_TCPFastOpenType
 {
   /**
    * Disable use of TCP_FASTOPEN.
    */
   MHD_FOM_DISABLE = -1
   ,
   /**
    * Enable TCP_FASTOPEN where supported.
    * On GNU/Linux it works with a kernel >= 3.6.
    * This is the default.
    */
   MHD_FOM_AUTO = 0
   ,
   /**
    * Require TCP_FASTOPEN.
    * Also causes #MHD_daemon_start() to fail if TCP_FASTOPEN cannot be enabled.
    */
   MHD_FOM_REQUIRE = 1
 };
 
 
 /**
  * Address family to be used by MHD.
  */
 enum MHD_FIXED_ENUM_APP_SET_ MHD_AddressFamily
 {
   /**
    * Option not given, do not listen at all
    * (unless listen socket or address specified by
    * other means).
    */
   MHD_AF_NONE = 0
   ,
   /**
    * Pick "best" available method automatically.
    */
   MHD_AF_AUTO = 1
   ,
   /**
    * Use IPv4 only.
    */
   MHD_AF_INET4 = 2
   ,
   /**
    * Use IPv6 only.
    */
   MHD_AF_INET6 = 3
   ,
   /**
    * Use dual stack (IPv4 and IPv6 on the same socket).
    */
   MHD_AF_DUAL = 4
   ,
   /**
    * Use dual stack (IPv4 and IPv6 on the same socket),
    * fallback to pure IPv6 if dual stack is not possible.
    */
   MHD_AF_DUAL_v4_OPTIONAL = 5
   ,
   /**
    * Use dual stack (IPv4 and IPv6 on the same socket),
    * fallback to pure IPv4 if dual stack is not possible.
    */
   MHD_AF_DUAL_v6_OPTIONAL = 6
 
 };
 
 
 /**
  * Sockets polling internal syscalls used by MHD.
  */
 enum MHD_FIXED_ENUM_APP_SET_ MHD_SockPollSyscall
 {
   /**
    * Automatic selection of best-available method. This is also the
    * default.
    */
   MHD_SPS_AUTO = 0
   ,
   /**
    * Use select().
    */
   MHD_SPS_SELECT = 1
   ,
   /**
    * Use poll().
    */
   MHD_SPS_POLL = 2
   ,
   /**
    * Use epoll.
    */
   MHD_SPS_EPOLL = 3
 };
 
 
 /**
  * Protocol strictness levels enforced by MHD on clients.
  * Each level applies different parsing settings for HTTP headers and other
  * protocol elements.
  */
 enum MHD_FIXED_ENUM_APP_SET_ MHD_ProtocolStrictLevel
 {
 
   /* * Basic levels * */
   /**
    * A sane default level of protocol enforcement for production use.
    * Provides a balance between enhanced security and broader compatibility,
    * as permitted by RFCs for HTTP servers.
    */
   MHD_PSL_DEFAULT = 0
   ,
   /**
    * Apply stricter protocol interpretation while remaining within
    * RFC-defined limits for HTTP servers.
    *
    * At this level (and stricter), using a bare LF instead of CRLF is forbidden,
    * and requests that include both a "Transfer-Encoding:" and
    * a "Content-Length:" headers are rejected.
    *
    * Suitable for public servers.
    */
   MHD_PSL_STRICT = 1
   ,
   /**
    * Be more permissive in interpreting the protocol, while still
    * operating within the RFC-defined limits for HTTP servers.
    */
   MHD_PSL_PERMISSIVE = -1
   ,
   /* * Special levels * */
   /**
    * A stricter protocol interpretation than what is allowed by RFCs for HTTP
    * servers. However, it should remain fully compatible with clients correctly
    * following all RFC "MUST" requirements for HTTP clients.
    *
    * For chunked encoding, this level (and more restrictive ones) forbids
    * whitespace in chunk extensions.
    * For cookie parsing, this level (and more restrictive ones) rejects
    * the entire cookie if even a single value within it is incorrectly encoded.
    *
    * Recommended for testing clients against MHD. Can also be used for
    * security-centric applications, though doing so slightly violates
    * relevant RFC requirements for HTTP servers.
    */
   MHD_PSL_VERY_STRICT = 2
   ,
   /**
    * The strictest interpretation of the HTTP protocol, even stricter than
    * allowed by RFCs for HTTP servers.
    * However, it should remain fully compatible with clients complying with both
    * RFC "SHOULD" and "MUST" requirements for HTTP clients.
    *
    * This level can be used for testing clients against MHD.
    * It is not recommended for public services, as it may reject legitimate
    * clients that do not follow RFC "SHOULD" requirements.
    */
   MHD_PSL_EXTRA_STRICT = 3
   ,
   /**
    * A more relaxed protocol interpretation that violates some RFC "SHOULD"
    * restrictions for HTTP servers.
    * For cookie parsing, this level (and more permissive levels) allows
    * whitespace in cookie values.
    *
    * This level may be used in isolated environments.
    */
   MHD_PSL_VERY_PERMISSIVE = -2
   ,
   /**
    * The most flexible protocol interpretation, going beyond RFC "MUST"
    * requirements for HTTP servers.
    *
    * This level allows HTTP/1.1 requests without a "Host:" header.
    * For cookie parsing, whitespace is allowed before and after
    * the '=' character.
    *
    * Not recommended unless absolutely necessary to communicate with clients
    * that have severely broken HTTP implementations.
    */
   MHD_PSL_EXTRA_PERMISSIVE = -3,
 };
 
 /**
  * The way Strict Level is enforced.
  * MHD can be compiled with limited set of strictness levels.
  * These values instructs MHD how to apply the request level.
  */
 enum MHD_FIXED_ENUM_APP_SET_ MHD_UseStictLevel
 {
   /**
    * Use requested level if available or the nearest stricter
    * level.
    * Fail if only more permissive levels available.
    * Recommended value.
    */
   MHD_USL_THIS_OR_STRICTER = 0
   ,
   /**
    * Use requested level only.
    * Fail if this level is not available.
    */
   MHD_USL_PRECISE = 1
   ,
   /**
    * Use requested level if available or the nearest level (stricter
    * or more permissive).
    */
   MHD_USL_NEAREST = 2
 };
 
 
 /**
  * Connection memory buffer zeroing mode.
  * Works as a hardening measure.
  */
 enum MHD_FIXED_ENUM_APP_SET_ MHD_ConnBufferZeroingMode
 {
   /**
    * Do not perform zeroing of connection memory buffer.
    * Default mode.
    */
   MHD_CONN_BUFFER_ZEROING_DISABLED = 0
   ,
   /**
    * Perform connection memory buffer zeroing before processing request.
    */
   MHD_CONN_BUFFER_ZEROING_BASIC = 1
   ,
   /**
    * Perform connection memory buffer zeroing before processing request and
    * when reusing buffer memory areas during processing request.
    */
   MHD_CONN_BUFFER_ZEROING_HEAVY = 2
 };
 
 
 /* ********************** (d) TLS support ********************** */
 
 /**
  * The TLS backend choice
  */
 enum MHD_FIXED_ENUM_APP_SET_ MHD_TlsBackend
 {
   /**
    * Disable TLS, use plain TCP connections (default)
    */
   MHD_TLS_BACKEND_NONE = 0
   ,
   /**
    * Use best available TLS backend.
    */
   MHD_TLS_BACKEND_ANY = 1
   ,
   /**
    * Use GnuTLS as TLS backend.
    */
   MHD_TLS_BACKEND_GNUTLS = 2
   ,
   /**
    * Use OpenSSL as TLS backend.
    */
   MHD_TLS_BACKEND_OPENSSL = 3
   ,
   /**
    * Use MbedTLS as TLS backend.
    */
   MHD_TLS_BACKEND_MBEDTLS = 4
 };
 
 /**
  * Values for #MHD_D_O_DAUTH_NONCE_BIND_TYPE.
  *
  * These values can limit the scope of validity of MHD-generated nonces.
  * Values can be combined with bitwise OR.
  * Any value, except #MHD_D_OPTION_VALUE_DAUTH_BIND_NONCE_NONE, enforce function
  * #MHD_digest_auth_check() (and similar functions) to check nonce by
  * re-generating it again with the same parameters, which is CPU-intensive
  * operation.
  */
 enum MHD_FIXED_FLAGS_ENUM_APP_SET_ MHD_DaemonOptionValueDAuthBindNonce
 {
   /**
    * Generated nonces are valid for any request from any client until expired.
    * This is default and recommended value.
    * #MHD_digest_auth_check() (and similar functions) would check only whether
    * the nonce value that is used by client has been generated by MHD and not
    * expired yet.
    * It is recommended because RFC 7616 allows clients to use the same nonce
    * for any request in the same "protection space".
    * When checking client's authorisation requests CPU is loaded less if this
    * value is used.
    * This mode gives MHD maximum flexibility for nonces generation and can
    * prevent possible nonce collisions (and corresponding log warning messages)
    * when clients' requests are intensive.
    * This value cannot be biwise-OR combined with other values.
    */
   MHD_D_OPTION_VALUE_DAUTH_BIND_NONCE_NONE = 0
   ,
   /**
    * Generated nonces are valid only for the same realm.
    */
   MHD_D_OPTION_VALUE_DAUTH_BIND_NONCE_REALM = (1 << 0)
   ,
   /**
    * Generated nonces are valid only for the same URI (excluding parameters
    * after '?' in URI) and request method (GET, POST etc).
    * Not recommended unless "protection space" is limited to a single URI as
    * RFC 7616 allows clients to reuse server-generated nonces for any URI
    * in the same "protection space" which by default consists of all server
    * URIs.
    */
   MHD_D_OPTION_VALUE_DAUTH_BIND_NONCE_URI = (1 << 1)
   ,
 
   /**
    * Generated nonces are valid only for the same URI including URI parameters
    * and request method (GET, POST etc).
    * This value implies #MHD_D_OPTION_VALUE_DAUTH_BIND_NONCE_URI.
    * Not recommended for that same reasons as
    * #MHD_D_OPTION_VALUE_DAUTH_BIND_NONCE_URI.
    */
   MHD_D_OPTION_VALUE_DAUTH_BIND_NONCE_URI_PARAMS = (1 << 2)
   ,
 
   /**
    * Generated nonces are valid only for the single client's IP.
    * While it looks like security improvement, in practice the same client may
    * jump from one IP to another (mobile or Wi-Fi handover, DHCP re-assignment,
    * Multi-NAT, different proxy chain and other reasons), while IP address
    * spoofing could be used relatively easily.
    */
   MHD_D_OPTION_VALUE_DAUTH_BIND_NONCE_CLIENT_IP = (1 << 3)
 };
 
 
 struct MHD_ServerCredentialsContext;
 
 
 /**
  * Context required to provide a pre-shared key to the
  * server.
  *
  * @param mscc the context
  * @param psk_size the number of bytes in @a psk
  * @param psk the pre-shared-key; should be allocated with malloc(),
  *                 will be freed by MHD
  */
 MHD_EXTERN_ enum MHD_StatusCode
 MHD_connection_set_psk (
   struct MHD_ServerCredentialsContext *mscc,
   size_t psk_size,
   const /*void? */ char psk[MHD_FN_PAR_DYN_ARR_SIZE_ (psk_size)]);
 
 #define MHD_connection_set_psk_unavailable(mscc) \
         MHD_connection_set_psk (mscc, 0, NULL)
 
 
 /**
  * Function called to lookup the pre-shared key (PSK) for a given
  * HTTP connection based on the @a username.  MHD will suspend handling of
  * the @a connection until the application calls #MHD_connection_set_psk().
  * If looking up the PSK fails, the application must still call
  * #MHD_connection_set_psk_unavailable().
  *
  * @param cls closure
  * @param connection the HTTPS connection
  * @param username the user name claimed by the other side
  * @param mscc context to pass to #MHD_connection_set_psk().
  */
 typedef void
 (*MHD_PskServerCredentialsCallback)(
   void *cls,
   const struct MHD_Connection *MHD_RESTRICT connection,
   const struct MHD_String *MHD_RESTRICT username,
   struct MHD_ServerCredentialsContext *mscc);
 
 
 /**
  * The specified callback will be called one time,
  * after network initialisation, TLS pre-initialisation, but before
  * the start of the internal threads (if allowed).
  *
  * This callback may use introspection call to retrieve and adjust
  * some of the daemon aspects. For example, TLS backend handler can be used
  * to configure some TLS aspects.
  * @param cls the callback closure
  */
 typedef void
 (*MHD_DaemonReadyCallback)(void *cls);
 
 
 /**
  * Allow or deny a client to connect.
  *
  * @param cls closure
  * @param addr_len length of @a addr
  * @param addr address information from the client
  * @see #MHD_D_OPTION_ACCEPT_POLICY()
  * @return #MHD_YES if connection is allowed, #MHD_NO if not
  */
 typedef enum MHD_Bool
 (*MHD_AcceptPolicyCallback)(void *cls,
                             size_t addr_len,
                             const struct sockaddr *addr);
 
 
 /**
  * The data for the #MHD_EarlyUriLogCallback
  */
 struct MHD_EarlyUriCbData
 {
   /**
    * The request handle.
    * Headers are not yet available.
    */
   struct MHD_Request *request;
 
   /**
    * The full URI ("request target") from the HTTP request, including URI
    * parameters (the part after '?')
    */
   struct MHD_String full_uri;
 
   /**
    * The request HTTP method
    */
   enum MHD_HTTP_Method method;
 };
 
 /**
  * Function called by MHD to allow the application to log the @a full_uri
  * of the new request.
  * This is the only moment when unmodified URI is provided.
  * After this callback MHD parses the URI and modifies it by extracting
  * GET parameters in-place.
  *
  * If this callback is set then it is the first application function called
  * for the new request.
  *
  * If #MHD_RequestEndedCallback is also set then it is guaranteed that
  * #MHD_RequestEndedCallback is called for the same request. Application
  * may allocate request specific data in this callback and de-allocate
  * the data in #MHD_RequestEndedCallback.
  *
  * @param cls client-defined closure
  * @param req_data the request data
  * @param request_app_context_ptr the pointer to variable that can be set to
  *                                the application context for the request;
  *                                initially the variable set to NULL
  */
 typedef void
 (MHD_FN_PAR_NONNULL_ALL_ MHD_FN_PAR_INOUT_ (3)
  *MHD_EarlyUriLogCallback)(void *cls,
                            const struct MHD_EarlyUriCbData *req_data,
                            void **request_app_context_ptr);
 
 
 /**
  * The `enum MHD_ConnectionNotificationCode` specifies types
  * of connection notifications.
  * @ingroup request
  */
 enum MHD_FIXED_ENUM_MHD_SET_ MHD_ConnectionNotificationCode
 {
 
   /**
    * A new connection has been started.
    * @ingroup request
    */
   MHD_CONNECTION_NOTIFY_STARTED = 0
   ,
   /**
    * A connection is closed.
    * @ingroup request
    */
   MHD_CONNECTION_NOTIFY_CLOSED = 1
 
 };
 
 /**
  * Extra details for connection notifications.
  * Currently not used
  */
 union MHD_ConnectionNotificationDetails
 {
   /**
    * Unused
    */
   int reserved1;
 };
 
 
 /**
  * The connection notification data structure
  */
 struct MHD_ConnectionNotificationData
 {
   /**
    * The connection handle
    */
   struct MHD_Connection *connection;
   /**
    * The connection-specific application context data (opaque for MHD).
    * Initially set to NULL (for connections added by MHD) or set by
    * @a connection_cntx parameter for connections added by
    * #MHD_daemon_add_connection().
    */
   void *application_context;
   /**
    * The code of the event
    */
   enum MHD_ConnectionNotificationCode code;
   /**
    * Event details
    */
   union MHD_ConnectionNotificationDetails details;
 };
 
 
 /**
  * Signature of the callback used by MHD to notify the
  * application about started/stopped network connections
  *
  * @param cls client-defined closure
  * @param[in,out]  data the details about the event
  * @see #MHD_D_OPTION_NOTIFY_CONNECTION()
  * @ingroup request
  */
 typedef void
 (MHD_FN_PAR_NONNULL_ (2)
  *MHD_NotifyConnectionCallback)(void *cls,
                                 struct MHD_ConnectionNotificationData *data);
 
 
 /**
  * The type of stream notifications.
  * @ingroup request
  */
 enum MHD_FIXED_ENUM_MHD_SET_ MHD_StreamNotificationCode
 {
   /**
    * A new stream has been started.
    * @ingroup request
    */
   MHD_STREAM_NOTIFY_STARTED = 0
   ,
   /**
    * A stream is closed.
    * @ingroup request
    */
   MHD_STREAM_NOTIFY_CLOSED = 1
 };
 
 /**
  * Additional information about stream started event
  */
 struct MHD_StreamNotificationDetailStarted
 {
   /**
    * Set to #MHD_YES of the stream was started by client
    */
   enum MHD_Bool by_client;
 };
 
 /**
  * Additional information about stream events
  */
 union MHD_StreamNotificationDetail
 {
   /**
    * Information for event #MHD_STREAM_NOTIFY_STARTED
    */
   struct MHD_StreamNotificationDetailStarted started;
 };
 
 /**
  * Stream notification data structure
  */
 struct MHD_StreamNotificationData
 {
   /**
    * The handle of the stream
    */
   struct MHD_Stream *stream;
   /**
    * The code of the event
    */
   enum MHD_StreamNotificationCode code;
   /**
    * Detailed information about notification event
    */
   union MHD_StreamNotificationDetail details;
 };
 
 
 /**
  * Signature of the callback used by MHD to notify the
  * application about started/stopped data stream
  * For HTTP/1.1 it is the same like network connection
  * with 1:1 match.
  *
  * @param cls client-defined closure
  * @param data the details about the event
  * @see #MHD_D_OPTION_NOTIFY_STREAM()
  * @ingroup request
  */
 typedef void
 (MHD_FN_PAR_NONNULL_ (2)
  *MHD_NotifyStreamCallback)(
   void *cls,
   const struct MHD_StreamNotificationData *data);
 
 #include "microhttpd2_generated_daemon_options.h"
 
 
 /**
  * The `enum MHD_RequestEndedCode` specifies reasons
  * why a request has been ended.
  * @ingroup request
  */
 enum MHD_FIXED_ENUM_MHD_SET_ MHD_RequestEndedCode
 {
 
   /**
    * The response was successfully sent.
    * @ingroup request
    */
   MHD_REQUEST_ENDED_COMPLETED_OK = 0
   ,
   /**
    * The response was successfully sent and connection is being switched
    * to another protocol.
    * @ingroup request
    */
   MHD_REQUEST_ENDED_COMPLETED_OK_UPGRADE = 1
   ,
   /**
    * No activity on the connection for the number of seconds specified using
    * #MHD_C_OPTION_TIMEOUT().
    * @ingroup request
    */
   MHD_REQUEST_ENDED_TIMEOUT_REACHED = 10
   ,
   /**
    * The connection was broken or TLS protocol error.
    * @ingroup request
    */
   MHD_REQUEST_ENDED_CONNECTION_ERROR = 20
   ,
   /**
    * The client terminated the connection by closing the socket either
    * completely or for writing (TCP half-closed) before sending complete
    * request.
    * @ingroup request
    */
   MHD_REQUEST_ENDED_CLIENT_ABORT = 30
   ,
   /**
    * The request is not valid according to HTTP specifications.
    * @ingroup request
    */
   MHD_REQUEST_ENDED_HTTP_PROTOCOL_ERROR = 31
   ,
   /**
    * The application aborted request without response.
    * @ingroup request
    */
   MHD_REQUEST_ENDED_BY_APP_ABORT = 40
   ,
   /**
    * The request was aborted due to the application failed to provide a valid
    * response.
    * @ingroup request
    */
   MHD_REQUEST_ENDED_BY_APP_ERROR = 41
   ,
   /**
    * The request was aborted due to the application failed to register external
    * event monitoring for the connection.
    * @ingroup request
    */
   MHD_REQUEST_ENDED_BY_EXT_EVENT_ERROR = 42
   ,
   /**
    * Error handling the connection due to resources exhausted.
    * @ingroup request
    */
   MHD_REQUEST_ENDED_NO_RESOURCES = 50
   ,
   /**
    * The request was aborted due to error reading file for file-backed response
    * @ingroup request
    */
   MHD_REQUEST_ENDED_FILE_ERROR = 51
   ,
   /**
    * The request was aborted due to error generating valid nonce for Digest Auth
    * @ingroup request
    */
   MHD_REQUEST_ENDED_NONCE_ERROR = 52
   ,
   /**
    * Closing the session since MHD is being shut down.
    * @ingroup request
    */
   MHD_REQUEST_ENDED_DAEMON_SHUTDOWN = 60
 };
 
 /**
  * Additional information about request ending
  */
 union MHD_RequestEndedDetail
 {
   /**
    * Reserved member.
    * Do not use.
    */
   void *reserved;
 };
 
 /**
  * Request termination data structure
  */
 struct MHD_RequestEndedData
 {
   /**
    * The request handle.
    * Note that most of the request data may be already unvailable.
    */
   struct MHD_Request *req;
   /**
    * The code of the event
    */
   enum MHD_RequestEndedCode code;
   /**
    * Detailed information about the event
    */
   union MHD_RequestEndedDetail details;
 };
 
 
 /**
  * Signature of the callback used by MHD to notify the application
  * about completed requests.
  *
  * This is the last callback called for any request (if provided by
  * the application).
  *
  * @param cls client-defined closure
  * @param data the details about the event
  * @param request_app_context the application request context, as possibly set
                               by the #MHD_EarlyUriLogCallback
  * @see #MHD_R_OPTION_TERMINATION_CALLBACK()
  * @ingroup request
  */
 typedef void
 (*MHD_RequestEndedCallback) (void *cls,
                              const struct MHD_RequestEndedData *data,
                              void *request_app_context);
 
 
 #include "microhttpd2_generated_response_options.h"