mhd_sockets: better sockets errors abstraction, improved performance on W32

5 files changed, 339 insertions, 518 deletions

diff --git a/src/microhttpd/connection.c b/src/microhttpd/connection.c
index 2c799d16..7c0ce674 100644
--- a/src/microhttpd/connection.c
+++ b/src/microhttpd/connection.c
@@ -1855,10 +1855,10 @@ do_read (struct MHD_Connection *connection)
                                      connection->read_buffer_offset);
   if (bytes_read < 0)
     {
-      const int err = MHD_socket_errno_;
-      if ((EINTR == err) || (EAGAIN == err) || (EWOULDBLOCK == err))
+      const int err = MHD_socket_get_error_ ();
+      if (MHD_SCKT_ERR_IS_EINTR_ (err) || MHD_SCKT_ERR_IS_EAGAIN_ (err))
 	  return MHD_NO;
-      if (ECONNRESET == err)
+      if (MHD_SCKT_ERR_IS_REMOTE_DISCNN_ (err))
         {
            CONNECTION_CLOSE_ERROR (connection, NULL);
 	   return MHD_NO;
@@ -1902,8 +1902,8 @@ do_write (struct MHD_Connection *connection)
 
   if (ret < 0)
     {
-      const int err = MHD_socket_errno_;
-      if ((EINTR == err) || (EAGAIN == err) || (EWOULDBLOCK == err))
+      const int err = MHD_socket_get_error_ ();
+      if (MHD_SCKT_ERR_IS_EINTR_ (err) || MHD_SCKT_ERR_IS_EAGAIN_ (err))
         return MHD_NO;
       CONNECTION_CLOSE_ERROR (connection, NULL);
       return MHD_YES;
@@ -2276,13 +2276,13 @@ MHD_connection_handle_write (struct MHD_Connection *connection)
                                       connection->continue_message_write_offset);
           if (ret < 0)
             {
-              const int err = MHD_socket_errno_;
-              if ((err == EINTR) || (err == EAGAIN) || (EWOULDBLOCK == err))
+              const int err = MHD_socket_get_error_ ();
+              if (MHD_SCKT_ERR_IS_EINTR_ (err) || MHD_SCKT_ERR_IS_EAGAIN_ (err))
                 break;
 #ifdef HAVE_MESSAGES
               MHD_DLOG (connection->daemon,
                         "Failed to send data: %s\n",
-                        MHD_socket_last_strerr_ ());
+                        MHD_socket_strerr_ (err));
 #endif
 	      CONNECTION_CLOSE_ERROR (connection, NULL);
               return MHD_YES;
@@ -2330,7 +2330,7 @@ MHD_connection_handle_write (struct MHD_Connection *connection)
                                         [(size_t)data_write_offset],
                                         response->data_size -
                                         (size_t)data_write_offset);
-            err = MHD_socket_errno_;
+            err = MHD_socket_get_error_ ();
 #if DEBUG_SEND_DATA
             if (ret > 0)
               fprintf (stderr,
@@ -2344,12 +2344,12 @@ MHD_connection_handle_write (struct MHD_Connection *connection)
               (void) MHD_mutex_unlock_ (&response->mutex);
             if (ret < 0)
               {
-                if ((err == EINTR) || (err == EAGAIN) || (EWOULDBLOCK == err))
+                if (MHD_SCKT_ERR_IS_EINTR_ (err) || MHD_SCKT_ERR_IS_EAGAIN_ (err))
                   return MHD_YES;
 #ifdef HAVE_MESSAGES
                 MHD_DLOG (connection->daemon,
                           "Failed to send data: %s\n",
-                          MHD_socket_last_strerr_ ());
+                          MHD_socket_strerr_ (err));
 #endif
                 CONNECTION_CLOSE_ERROR (connection, NULL);
                 return MHD_YES;
diff --git a/src/microhttpd/daemon.c b/src/microhttpd/daemon.c
index 7a784daf..68491938 100644
--- a/src/microhttpd/daemon.c
+++ b/src/microhttpd/daemon.c
@@ -457,7 +457,7 @@ recv_tls_adapter (struct MHD_Connection *connection, void *other, size_t i)
   if ( (GNUTLS_E_AGAIN == res) ||
        (GNUTLS_E_INTERRUPTED == res) )
     {
-      MHD_set_socket_errno_ (EINTR);
+      MHD_socket_set_error_ (MHD_SCKT_EINTR_);
 #if EPOLL_SUPPORT
       connection->epoll_state &= ~MHD_EPOLL_STATE_READ_READY;
 #endif
@@ -468,7 +468,7 @@ recv_tls_adapter (struct MHD_Connection *connection, void *other, size_t i)
       /* Likely 'GNUTLS_E_INVALID_SESSION' (client communication
 	 disrupted); set errno to something caller will interpret
 	 correctly as a hard error */
-      MHD_set_socket_errno_ (ECONNRESET);
+      MHD_socket_set_error_ (MHD_SCKT_ECONNRESET_);
       return res;
     }
   if ((size_t)res == i)
@@ -498,7 +498,7 @@ send_tls_adapter (struct MHD_Connection *connection,
   if ( (GNUTLS_E_AGAIN == res) ||
        (GNUTLS_E_INTERRUPTED == res) )
     {
-      MHD_set_socket_errno_ (EINTR);
+      MHD_socket_set_error_ (MHD_SCKT_EINTR_);
 #if EPOLL_SUPPORT
       connection->epoll_state &= ~MHD_EPOLL_STATE_WRITE_READY;
 #endif
@@ -510,7 +510,7 @@ send_tls_adapter (struct MHD_Connection *connection,
          really understand the error (not listed in GnuTLS
          documentation explicitly), we set 'errno' to something that
          will cause the connection to fail. */
-      MHD_set_socket_errno_ (ECONNRESET);
+      MHD_socket_set_error_ (MHD_SCKT_ECONNRESET_);
       return -1;
     }
   return res;
@@ -971,13 +971,14 @@ MHD_handle_connection (void *data)
 	  num_ready = MHD_SYS_select_ (maxsock + 1, &rs, &ws, NULL, tvp);
 	  if (num_ready < 0)
 	    {
-	      if (EINTR == MHD_socket_errno_)
+	      const int err = MHD_socket_get_error_();
+	      if (MHD_SCKT_ERR_IS_EINTR_(err))
 		continue;
 #ifdef HAVE_MESSAGES
 	      MHD_DLOG (con->daemon,
 			"Error during select (%d): `%s'\n",
-			MHD_socket_errno_,
-			MHD_socket_last_strerr_ ());
+			err,
+			MHD_socket_strerr_ (err));
 #endif
 	      break;
 	    }
@@ -1039,7 +1040,7 @@ MHD_handle_connection (void *data)
 #endif
 		    (NULL == tvp) ? -1 : tv.tv_sec * 1000) < 0)
 	    {
-	      if (EINTR == MHD_socket_errno_)
+	      if (MHD_SCKT_LAST_ERR_IS_(MHD_SCKT_EINTR_))
 		continue;
 #ifdef HAVE_MESSAGES
 	      MHD_DLOG (con->daemon,
@@ -1117,7 +1118,7 @@ recv_param_adapter (struct MHD_Connection *connection,
   if ( (MHD_INVALID_SOCKET == connection->socket_fd) ||
        (MHD_CONNECTION_CLOSED == connection->state) )
     {
-      MHD_set_socket_errno_ (ENOTCONN);
+      MHD_socket_set_error_ (MHD_SCKT_ENOTCONN_);
       return -1;
     }
 #ifdef MHD_POSIX_SOCKETS
@@ -1133,7 +1134,7 @@ recv_param_adapter (struct MHD_Connection *connection,
                         (_MHD_socket_funcs_size) i,
                         MSG_NOSIGNAL);
 #if EPOLL_SUPPORT
-  if ( (0 > ret) && (EAGAIN == MHD_socket_errno_) )
+  if ( (0 > ret) && (MHD_SCKT_ERR_IS_EAGAIN_ (MHD_socket_get_error_ ())) )
     {
       /* Got EAGAIN --- no longer read-ready */
       connection->epoll_state &= ~MHD_EPOLL_STATE_READ_READY;
@@ -1157,6 +1158,7 @@ send_param_adapter (struct MHD_Connection *connection,
 		    size_t i)
 {
   ssize_t ret;
+  int err;
 #if LINUX
   MHD_socket fd;
 #endif
@@ -1164,7 +1166,7 @@ send_param_adapter (struct MHD_Connection *connection,
   if ( (MHD_INVALID_SOCKET == connection->socket_fd) ||
        (MHD_CONNECTION_CLOSED == connection->state) )
     {
-      MHD_set_socket_errno_ (ENOTCONN);
+      MHD_socket_set_error_ (MHD_SCKT_ENOTCONN_);
       return -1;
     }
 #ifdef MHD_POSIX_SOCKETS
@@ -1189,7 +1191,6 @@ send_param_adapter (struct MHD_Connection *connection,
       /* can use sendfile */
       uint64_t left;
       uint64_t offsetu64;
-      int err;
 #ifndef HAVE_SENDFILE64
       off_t offset;
 #else  /* HAVE_SENDFILE64 */
@@ -1198,7 +1199,7 @@ send_param_adapter (struct MHD_Connection *connection,
       offsetu64 = connection->response_write_position + connection->response->fd_off;
       left = connection->response->total_size - connection->response_write_position;
       ret = 0;
-      MHD_set_socket_errno_(ENOMEM);
+      MHD_socket_set_error_to_ENOMEM ();
 #ifndef HAVE_SENDFILE64
       offset = (off_t) offsetu64;
       if ( (offsetu64 <= (uint64_t) OFF_T_MAX) &&
@@ -1212,17 +1213,17 @@ send_param_adapter (struct MHD_Connection *connection,
           /* write successful */
           return ret;
         }
-      err = MHD_socket_errno_;
+      err = MHD_socket_get_error_();
 #if EPOLL_SUPPORT
-      if ( (0 > ret) && (EAGAIN == err) )
+      if ( (0 > ret) && (MHD_SCKT_ERR_IS_EAGAIN_(err)) )
         {
           /* EAGAIN --- no longer write-ready */
           connection->epoll_state &= ~MHD_EPOLL_STATE_WRITE_READY;
         }
 #endif
-      if ( (EINTR == err) || (EAGAIN == err) || (EWOULDBLOCK == err) )
+      if (MHD_SCKT_ERR_IS_EINTR_ (err) || MHD_SCKT_ERR_IS_EAGAIN_ (err))
 	return 0;
-      if (EBADF == err)
+      if (MHD_SCKT_ERR_IS_(err, MHD_SCKT_EBADF_))
 	return -1;
       /* sendfile() failed with EINVAL if mmap()-like operations are not
 	 supported for FD or other 'unusual' errors occurred, so we should try
@@ -1232,8 +1233,9 @@ send_param_adapter (struct MHD_Connection *connection,
     }
 #endif
   ret = (ssize_t) send (connection->socket_fd, other, (_MHD_socket_funcs_size)i, MSG_NOSIGNAL);
+  err = MHD_socket_get_error_();
 #if EPOLL_SUPPORT
-  if ( (0 > ret) && (EAGAIN == MHD_socket_errno_) )
+  if ( (0 > ret) && (MHD_SCKT_ERR_IS_EAGAIN_(err)) )
     {
       /* EAGAIN --- no longer write-ready */
       connection->epoll_state &= ~MHD_EPOLL_STATE_WRITE_READY;
@@ -1242,8 +1244,8 @@ send_param_adapter (struct MHD_Connection *connection,
   /* Handle broken kernel / libc, returning -1 but not setting errno;
      kill connection as that should be safe; reported on mailinglist here:
      http://lists.gnu.org/archive/html/libmicrohttpd/2014-10/msg00023.html */
-  if ( (0 > ret) && (0 == MHD_socket_errno_) )
-    MHD_set_socket_errno_(ECONNRESET);
+  if ( (0 > ret) && (0 == err) )
+    MHD_socket_set_error_ (MHD_SCKT_ECONNRESET_);
   return ret;
 }
 
@@ -1970,16 +1972,18 @@ MHD_accept_connection (struct MHD_Daemon *daemon)
 #endif /* ! USE_ACCEPT4 */
   if ((MHD_INVALID_SOCKET == s) || (addrlen <= 0))
     {
-      const int err = MHD_socket_errno_;
+      const int err = MHD_socket_get_error_ ();
       /* This could be a common occurance with multiple worker threads */
-      if ( (EINVAL == err) &&
+      if ( (MHD_SCKT_ERR_IS_ (err, MHD_SCKT_EINVAL_)) &&
            (MHD_INVALID_SOCKET == daemon->socket_fd) )
         return MHD_NO; /* can happen during shutdown */
+      if (MHD_SCKT_ERR_IS_DISCNN_BEFORE_ACCEPT_(err))
+        return MHD_NO; /* do not print error if client just disconnected early */
 #ifdef HAVE_MESSAGES
-      if ((EAGAIN != err) && (EWOULDBLOCK != err))
+      if ( !MHD_SCKT_ERR_IS_EAGAIN_ (err) )
         MHD_DLOG (daemon,
 		  "Error accepting connection: %s\n",
-		  MHD_socket_last_strerr_ ());
+		  MHD_socket_strerr_(err));
 #endif
       if (MHD_INVALID_SOCKET != s)
         {
@@ -1987,10 +1991,7 @@ MHD_accept_connection (struct MHD_Daemon *daemon)
 	    MHD_PANIC ("close failed\n");
           /* just in case */
         }
-      if ( (EMFILE == err) ||
-           (ENFILE == err) ||
-           (ENOMEM == err) ||
-           (ENOBUFS == err) )
+      if ( MHD_SCKT_ERR_IS_LOW_RESOURCES_ (err) )
         {
           /* system/process out of resources */
           if (0 == daemon->connections)
@@ -2430,12 +2431,13 @@ MHD_select (struct MHD_Daemon *daemon,
     return MHD_NO;
   if (num_ready < 0)
     {
-      if (EINTR == MHD_socket_errno_)
+      const int err = MHD_socket_get_error_ ();
+      if (MHD_SCKT_ERR_IS_EINTR_(err))
         return (MHD_NO == err_state) ? MHD_YES : MHD_NO;
 #ifdef HAVE_MESSAGES
       MHD_DLOG (daemon,
                 "select failed: %s\n",
-                MHD_socket_last_strerr_ ());
+                MHD_socket_strerr_ (err));
 #endif
       return MHD_NO;
     }
@@ -2551,7 +2553,8 @@ MHD_poll_all (struct MHD_Daemon *daemon,
       }
     if (MHD_sys_poll_(p, poll_server + num_connections, timeout) < 0)
       {
-	if (EINTR == MHD_socket_errno_)
+        const int err = MHD_socket_get_error_ ();
+	if (MHD_SCKT_ERR_IS_EINTR_ (err))
       {
         free(p);
         return MHD_YES;
@@ -2559,7 +2562,7 @@ MHD_poll_all (struct MHD_Daemon *daemon,
 #ifdef HAVE_MESSAGES
 	MHD_DLOG (daemon,
 		  "poll failed: %s\n",
-		  MHD_socket_last_strerr_ ());
+		  MHD_socket_strerr_ (err));
 #endif
         free(p);
 	return MHD_NO;
@@ -2645,12 +2648,13 @@ MHD_poll_listen_socket (struct MHD_Daemon *daemon,
     return MHD_YES;
   if (MHD_sys_poll_(p, poll_count, timeout) < 0)
     {
-      if (EINTR == MHD_socket_errno_)
+      const int err = MHD_socket_get_error_ ();
+      if (MHD_SCKT_ERR_IS_EINTR_ (err))
 	return MHD_YES;
 #ifdef HAVE_MESSAGES
       MHD_DLOG (daemon,
                 "poll failed: %s\n",
-                MHD_socket_last_strerr_ ());
+                MHD_socket_strerr_ (err));
 #endif
       return MHD_NO;
     }
@@ -2790,12 +2794,13 @@ MHD_epoll (struct MHD_Daemon *daemon,
 			       events, MAX_EVENTS, timeout_ms);
       if (-1 == num_events)
 	{
-	  if (EINTR == MHD_socket_errno_)
+          const int err = MHD_socket_get_error_ ();
+          if (MHD_SCKT_ERR_IS_EINTR_ (err))
 	    return MHD_YES;
 #ifdef HAVE_MESSAGES
           MHD_DLOG (daemon,
                     "Call to epoll_wait failed: %s\n",
-                    MHD_socket_last_strerr_ ());
+                    MHD_socket_strerr_ (err));
 #endif
 	  return MHD_NO;
 	}
diff --git a/src/microhttpd/mhd_compat.h b/src/microhttpd/mhd_compat.h
index 3f88055f..19ebac5f 100644
--- a/src/microhttpd/mhd_compat.h
+++ b/src/microhttpd/mhd_compat.h
@@ -36,6 +36,12 @@
 
 #include "mhd_options.h"
 #include <stdlib.h>
+#ifdef HAVE_STRING_H /* for strerror() */
+#include <string.h>
+#endif /* HAVE_STRING_H */
+
+ /* MHD_strerror_ is strerror */
+#define MHD_strerror_(errnum) strerror((errnum))
 
 /* Platform-independent snprintf name */
 #if defined(HAVE_SNPRINTF)
diff --git a/src/microhttpd/mhd_sockets.c b/src/microhttpd/mhd_sockets.c
index 4214108e..643ed849 100644
--- a/src/microhttpd/mhd_sockets.c
+++ b/src/microhttpd/mhd_sockets.c
@@ -29,166 +29,13 @@
 #ifdef MHD_WINSOCK_SOCKETS
 
 /**
- * Return errno equivalent of last winsock error
- * @return errno equivalent of last winsock error
+ * Return pointer to string description of specified WinSock error
+ * @param err the WinSock error code.
+ * @return pointer to string description of specified WinSock error.
  */
-int MHD_W32_errno_from_winsock_(void)
+const char* MHD_W32_strerror_winsock_(int err)
 {
-  switch(WSAGetLastError())
-  {
-  case 0:                      return 0;
-  case WSA_INVALID_HANDLE:     return EBADF;
-  case WSA_NOT_ENOUGH_MEMORY:  return ENOMEM;
-  case WSA_INVALID_PARAMETER:  return EINVAL;
-  case WSAEINTR:               return EINTR;
-  case WSAEWOULDBLOCK:         return EWOULDBLOCK;
-  case WSAEINPROGRESS:         return EINPROGRESS;
-  case WSAEALREADY:            return EALREADY;
-  case WSAENOTSOCK:            return ENOTSOCK;
-  case WSAEDESTADDRREQ:        return EDESTADDRREQ;
-  case WSAEMSGSIZE:            return EMSGSIZE;
-  case WSAEPROTOTYPE:          return EPROTOTYPE;
-  case WSAENOPROTOOPT:         return ENOPROTOOPT;
-  case WSAEPROTONOSUPPORT:     return EPROTONOSUPPORT;
-  case WSAESOCKTNOSUPPORT:     return ESOCKTNOSUPPORT;
-  case WSAEOPNOTSUPP:          return EOPNOTSUPP;
-  case WSAEPFNOSUPPORT:        return EPFNOSUPPORT;
-  case WSAEAFNOSUPPORT:        return EAFNOSUPPORT;
-  case WSAEADDRINUSE:          return EADDRINUSE;
-  case WSAEADDRNOTAVAIL:       return EADDRNOTAVAIL;
-  case WSAENETDOWN:            return ENETDOWN;
-  case WSAENETUNREACH:         return ENETUNREACH;
-  case WSAENETRESET:           return ENETRESET;
-  case WSAECONNABORTED:        return ECONNABORTED;
-  case WSAECONNRESET:          return ECONNRESET;
-  case WSAENOBUFS:             return ENOBUFS;
-  case WSAEISCONN:             return EISCONN;
-  case WSAENOTCONN:            return ENOTCONN;
-  case WSAESHUTDOWN:           return ESHUTDOWN;
-  case WSAETOOMANYREFS:        return ETOOMANYREFS;
-  case WSAETIMEDOUT:           return ETIMEDOUT;
-  case WSAECONNREFUSED:        return ECONNREFUSED;
-  case WSAELOOP:               return ELOOP;
-  case WSAENAMETOOLONG:        return ENAMETOOLONG;
-  case WSAEHOSTDOWN:           return EHOSTDOWN;
-  case WSAEHOSTUNREACH:        return EHOSTUNREACH;
-  case WSAENOTEMPTY:           return ENOTEMPTY;
-  case WSAEPROCLIM:            return EPROCLIM;
-  case WSAEUSERS:              return EUSERS;
-  case WSAEDQUOT:              return EDQUOT;
-  case WSAESTALE:              return ESTALE;
-  case WSAEREMOTE:             return EREMOTE;
-  case WSAEINVAL:              return EINVAL;
-  case WSAEFAULT:              return EFAULT;
-  case WSANO_DATA:             return ENODATA;
-  /* Rough equivalents */
-  case WSAEDISCON:             return ECONNRESET;
-  case WSAEINVALIDPROCTABLE:   return EFAULT;
-  case WSASYSNOTREADY:
-  case WSANOTINITIALISED:
-  case WSASYSCALLFAILURE:      return ENOBUFS;
-  case WSAVERNOTSUPPORTED:     return EOPNOTSUPP;
-  case WSAEREFUSED:            return EIO;
-  }
-  return EINVAL;
-}
-
-/**
- * Return pointer to string description of errnum error
- * Works fine with both standard errno errnums
- * and errnums from MHD_W32_errno_from_winsock_
- * @param errnum the errno or value from MHD_W32_errno_from_winsock_()
- * @return pointer to string description of error
- */
-const char* MHD_W32_strerror_(int errnum)
-{
-  switch(errnum)
-  {
-  case 0:
-    return "No error";
-  case EWOULDBLOCK:
-    return "Operation would block";
-  case EINPROGRESS:
-    return "Connection already in progress";
-  case EALREADY:
-    return "Socket already connected";
-  case ENOTSOCK:
-    return "Socket operation on non-socket";
-  case EDESTADDRREQ:
-    return "Destination address required";
-  case EMSGSIZE:
-    return "Message too long";
-  case EPROTOTYPE:
-    return "Protocol wrong type for socket";
-  case ENOPROTOOPT:
-    return "Protocol not available";
-  case EPROTONOSUPPORT:
-    return "Unknown protocol";
-  case ESOCKTNOSUPPORT:
-    return "Socket type not supported";
-  case EOPNOTSUPP:
-    return "Operation not supported on socket";
-  case EPFNOSUPPORT:
-    return "Protocol family not supported";
-  case EAFNOSUPPORT:
-    return "Address family not supported by protocol family";
-  case EADDRINUSE:
-    return "Address already in use";
-  case EADDRNOTAVAIL:
-    return "Cannot assign requested address";
-  case ENETDOWN:
-    return "Network is down";
-  case ENETUNREACH:
-    return "Network is unreachable";
-  case ENETRESET:
-    return "Network dropped connection on reset";
-  case ECONNABORTED:
-    return "Software caused connection abort";
-  case ECONNRESET:
-    return "Connection reset by peer";
-  case ENOBUFS:
-    return "No system resources available";
-  case EISCONN:
-    return "Socket is already connected";
-  case ENOTCONN:
-    return "Socket is not connected";
-  case ESHUTDOWN:
-    return "Can't send after socket shutdown";
-  case ETOOMANYREFS:
-    return "Too many references: cannot splice";
-  case ETIMEDOUT:
-    return "Connection timed out";
-  case ECONNREFUSED:
-    return "Connection refused";
-  case ELOOP:
-    return "Cannot translate name";
-  case EHOSTDOWN:
-    return "Host is down";
-  case EHOSTUNREACH:
-    return "Host is unreachable";
-  case EPROCLIM:
-    return "Too many processes";
-  case EUSERS:
-    return "Too many users";
-  case EDQUOT:
-    return "Disk quota exceeded";
-  case ESTALE:
-    return "Stale file handle reference";
-  case EREMOTE:
-    return "Resource is remote";
-  case ENODATA:
-    return "No data available";
-  }
-  return strerror(errnum);
-}
-
-/**
- * Return pointer to string description of last winsock error
- * @return pointer to string description of last winsock error
- */
-const char* MHD_W32_strerror_last_winsock_(void)
-{
-  switch (WSAGetLastError())
+  switch (err)
     {
   case 0:
     return "No error";
@@ -386,160 +233,5 @@ const char* MHD_W32_strerror_last_winsock_(void)
   return "Unknown winsock error";
 }
 
-/**
- * Set last winsock error to equivalent of given errno value
- * @param errnum the errno value to set
- */
-void MHD_W32_set_last_winsock_error_(int errnum)
-{
-  switch (errnum)
-    {
-  case 0:
-    WSASetLastError(0);
-    break;
-  case EBADF:
-    WSASetLastError(WSA_INVALID_HANDLE);
-    break;
-  case ENOMEM:
-    WSASetLastError(WSA_NOT_ENOUGH_MEMORY);
-    break;
-  case EINVAL:
-    WSASetLastError(WSA_INVALID_PARAMETER);
-    break;
-  case EINTR:
-    WSASetLastError(WSAEINTR);
-    break;
-  case EWOULDBLOCK:
-    WSASetLastError(WSAEWOULDBLOCK);
-    break;
-  case EINPROGRESS:
-    WSASetLastError(WSAEINPROGRESS);
-    break;
-  case EALREADY:
-    WSASetLastError(WSAEALREADY);
-    break;
-  case ENOTSOCK:
-    WSASetLastError(WSAENOTSOCK);
-    break;
-  case EDESTADDRREQ:
-    WSASetLastError(WSAEDESTADDRREQ);
-    break;
-  case EMSGSIZE:
-    WSASetLastError(WSAEMSGSIZE);
-    break;
-  case EPROTOTYPE:
-    WSASetLastError(WSAEPROTOTYPE);
-    break;
-  case ENOPROTOOPT:
-    WSASetLastError(WSAENOPROTOOPT);
-    break;
-  case EPROTONOSUPPORT:
-    WSASetLastError(WSAEPROTONOSUPPORT);
-    break;
-  case ESOCKTNOSUPPORT:
-    WSASetLastError(WSAESOCKTNOSUPPORT);
-    break;
-  case EOPNOTSUPP:
-    WSASetLastError(WSAEOPNOTSUPP);
-    break;
-  case EPFNOSUPPORT:
-    WSASetLastError(WSAEPFNOSUPPORT);
-    break;
-  case EAFNOSUPPORT:
-    WSASetLastError(WSAEAFNOSUPPORT);
-    break;
-  case EADDRINUSE:
-    WSASetLastError(WSAEADDRINUSE);
-    break;
-  case EADDRNOTAVAIL:
-    WSASetLastError(WSAEADDRNOTAVAIL);
-    break;
-  case ENETDOWN:
-    WSASetLastError(WSAENETDOWN);
-    break;
-  case ENETUNREACH:
-    WSASetLastError(WSAENETUNREACH);
-    break;
-  case ENETRESET:
-    WSASetLastError(WSAENETRESET);
-    break;
-  case ECONNABORTED:
-    WSASetLastError(WSAECONNABORTED);
-    break;
-  case ECONNRESET:
-    WSASetLastError(WSAECONNRESET);
-    break;
-  case ENOBUFS:
-    WSASetLastError(WSAENOBUFS);
-    break;
-  case EISCONN:
-    WSASetLastError(WSAEISCONN);
-    break;
-  case ENOTCONN:
-    WSASetLastError(WSAENOTCONN);
-    break;
-  case ESHUTDOWN:
-    WSASetLastError(WSAESHUTDOWN);
-    break;
-  case ETOOMANYREFS:
-    WSASetLastError(WSAETOOMANYREFS);
-    break;
-  case ETIMEDOUT:
-    WSASetLastError(WSAETIMEDOUT);
-    break;
-  case ECONNREFUSED:
-    WSASetLastError(WSAECONNREFUSED);
-    break;
-  case ELOOP:
-    WSASetLastError(WSAELOOP);
-    break;
-  case ENAMETOOLONG:
-    WSASetLastError(WSAENAMETOOLONG);
-    break;
-  case EHOSTDOWN:
-    WSASetLastError(WSAEHOSTDOWN);
-    break;
-  case EHOSTUNREACH:
-    WSASetLastError(WSAEHOSTUNREACH);
-    break;
-  case ENOTEMPTY:
-    WSASetLastError(WSAENOTEMPTY);
-    break;
-  case EPROCLIM:
-    WSASetLastError(WSAEPROCLIM);
-    break;
-  case EUSERS:
-    WSASetLastError(WSAEUSERS);
-    break;
-  case EDQUOT:
-    WSASetLastError(WSAEDQUOT);
-    break;
-  case ESTALE:
-    WSASetLastError(WSAESTALE);
-    break;
-  case EREMOTE:
-    WSASetLastError(WSAEREMOTE);
-    break;
-  case EFAULT:
-    WSASetLastError(WSAEFAULT);
-    break;
-  case ENODATA:
-    WSASetLastError(WSANO_DATA);
-    break;
-#if EAGAIN != EWOULDBLOCK
-  case EAGAIN:
-    WSASetLastError(WSAEWOULDBLOCK);
-    break;
-#endif
-  /* Rough equivalent */
-  case EIO:
-    WSASetLastError(WSAEREFUSED);
-    break;
-
-  default: /* Unmapped errors */
-    WSASetLastError(WSAENOBUFS);
-    break;
-    }
-}
 
 #endif /* MHD_WINSOCK_SOCKETS */
diff --git a/src/microhttpd/mhd_sockets.h b/src/microhttpd/mhd_sockets.h
index 3a3e4b85..b38a5d55 100644
--- a/src/microhttpd/mhd_sockets.h
+++ b/src/microhttpd/mhd_sockets.h
@@ -204,38 +204,6 @@
 #  define MHD_socket_close_(fd) closesocket((fd))
 #endif
 
-/**
- * MHD_socket_errno_ is errno of last function (non-W32) / errno of
- * last socket function (W32)
- */
-#if !defined(MHD_WINSOCK_SOCKETS)
-#  define MHD_socket_errno_ errno
-#else
-#  define MHD_socket_errno_ MHD_W32_errno_from_winsock_()
-#endif
-
- /* MHD_socket_last_strerr_ is description string of last errno (non-W32) /
-  *                            description string of last socket error (W32) */
-#if !defined(MHD_WINSOCK_SOCKETS)
-#  define MHD_socket_last_strerr_() strerror(errno)
-#else
-#  define MHD_socket_last_strerr_() MHD_W32_strerror_last_winsock_()
-#endif
-
- /* MHD_strerror_ is strerror (both non-W32/W32) */
-#if !defined(MHD_WINSOCK_SOCKETS)
-#  define MHD_strerror_(errnum) strerror((errnum))
-#else
-#  define MHD_strerror_(errnum) MHD_W32_strerror_((errnum))
-#endif
-
- /* MHD_set_socket_errno_ set errno to errnum (non-W32) / set socket last error to errnum (W32) */
-#if !defined(MHD_WINSOCK_SOCKETS)
-#  define MHD_set_socket_errno_(errnum) errno=(errnum)
-#else
-#  define MHD_set_socket_errno_(errnum) MHD_W32_set_last_winsock_error_((errnum))
-#endif
-
  /* MHD_SYS_select_ is wrapper macro for system select() function */
 #if !defined(MHD_WINSOCK_SOCKETS)
 #  define MHD_SYS_select_(n,r,w,e,t) select((n),(r),(w),(e),(t))
@@ -257,150 +225,300 @@
 #  endif /* MHD_WINSOCK_SOCKETS */
 #endif /* HAVE_POLL */
 
+#define MHD_SCKT_MISSING_ERR_CODE_ 31450
+
+#if defined(MHD_POSIX_SOCKETS)
+#  if defined(EAGAIN)
+#    define MHD_SCKT_EAGAIN_      EAGAIN
+#  elif defined(EWOULDBLOCK)
+#    define MHD_SCKT_EAGAIN_      EWOULDBLOCK
+#  else  /* !EAGAIN && !EWOULDBLOCK */
+#    define MHD_SCKT_EAGAIN_      MHD_SCKT_MISSING_ERR_CODE_
+#  endif /* !EAGAIN && !EWOULDBLOCK */
+#  if defined(EWOULDBLOCK)
+#    define MHD_SCKT_EWOULDBLOCK_ EWOULDBLOCK
+#  elif defined(EAGAIN)
+#    define MHD_SCKT_EWOULDBLOCK_ EAGAIN
+#  else  /* !EWOULDBLOCK && !EAGAIN */
+#    define MHD_SCKT_EWOULDBLOCK_ MHD_SCKT_MISSING_ERR_CODE_
+#  endif /* !EWOULDBLOCK && !EAGAIN */
+#  ifdef EINTR
+#    define MHD_SCKT_EINTR_       EINTR
+#  else  /* ! EINTR */
+#    define MHD_SCKT_EINTR_       MHD_SCKT_MISSING_ERR_CODE_
+#  endif /* ! EINTR */
+#  ifdef ECONNRESET
+#    define MHD_SCKT_ECONNRESET_  ECONNRESET
+#  else  /* ! ECONNRESET */
+#    define MHD_SCKT_ECONNRESET_  MHD_SCKT_MISSING_ERR_CODE_
+#  endif /* ! ECONNRESET */
+#  ifdef ECONNABORTED
+#    define MHD_SCKT_ECONNABORTED_  ECONNABORTED
+#  else  /* ! ECONNABORTED */
+#    define MHD_SCKT_ECONNABORTED_  MHD_SCKT_MISSING_ERR_CODE_
+#  endif /* ! ECONNABORTED */
+#  ifdef ENOTCONN
+#    define MHD_SCKT_ENOTCONN_    ENOTCONN
+#  else  /* ! ENOTCONN */
+#    define MHD_SCKT_ENOTCONN_    MHD_SCKT_MISSING_ERR_CODE_
+#  endif /* ! ENOTCONN */
+#  ifdef EMFILE
+#    define MHD_SCKT_EMFILE_      EMFILE
+#  else  /* ! EMFILE */
+#    define MHD_SCKT_EMFILE_      MHD_SCKT_MISSING_ERR_CODE_
+#  endif /* ! EMFILE */
+#  ifdef ENFILE
+#    define MHD_SCKT_ENFILE_      ENFILE
+#  else  /* ! ENFILE */
+#    define MHD_SCKT_ENFILE_      MHD_SCKT_MISSING_ERR_CODE_
+#  endif /* ! ENFILE */
+#  ifdef ENOMEM
+#    define MHD_SCKT_ENOMEM_      ENOMEM
+#  else  /* ! ENOMEM */
+#    define MHD_SCKT_ENOMEM_      MHD_SCKT_MISSING_ERR_CODE_
+#  endif /* ! ENOMEM */
+#  ifdef ENOBUFS
+#    define MHD_SCKT_ENOBUFS_     ENOBUFS
+#  else  /* ! ENOBUFS */
+#    define MHD_SCKT_ENOBUFS_     MHD_SCKT_MISSING_ERR_CODE_
+#  endif /* ! ENOBUFS */
+#  ifdef EBADF
+#    define MHD_SCKT_EBADF_       EBADF
+#  else  /* ! EBADF */
+#    define MHD_SCKT_EBADF_       MHD_SCKT_MISSING_ERR_CODE_
+#  endif /* ! EBADF */
+#  ifdef ENOTSOCK
+#    define MHD_SCKT_ENOTSOCK_    ENOTSOCK
+#  else  /* ! ENOTSOCK */
+#    define MHD_SCKT_ENOTSOCK_    MHD_SCKT_MISSING_ERR_CODE_
+#  endif /* ! ENOTSOCK */
+#  ifdef EINVAL
+#    define MHD_SCKT_EINVAL_      EINVAL
+#  else  /* ! EINVAL */
+#    define MHD_SCKT_EINVAL_      MHD_SCKT_MISSING_ERR_CODE_
+#  endif /* ! EINVAL */
+#  ifdef EFAULT
+#    define MHD_SCKT_EFAUL_       EFAULT
+#  else  /* ! EFAULT */
+#    define MHD_SCKT_EFAUL_       MHD_SCKT_MISSING_ERR_CODE_
+#  endif /* ! EFAULT */
+#  ifdef ENOSYS
+#    define MHD_SCKT_ENOSYS_      ENOSYS
+#  else  /* ! ENOSYS */
+#    define MHD_SCKT_ENOSYS_      MHD_SCKT_MISSING_ERR_CODE_
+#  endif /* ! ENOSYS */
+#  ifdef ENOTSUP
+#    define MHD_SCKT_ENOTSUP_     ENOTSUP
+#  else  /* ! ENOTSUP */
+#    define MHD_SCKT_ENOTSUP_     MHD_SCKT_MISSING_ERR_CODE_
+#  endif /* ! ENOTSUP */
+#  ifdef EOPNOTSUPP
+#    define MHD_SCKT_EOPNOTSUPP_  EOPNOTSUPP
+#  else  /* ! EOPNOTSUPP */
+#    define MHD_SCKT_EOPNOTSUPP_  MHD_SCKT_MISSING_ERR_CODE_
+#  endif /* ! EOPNOTSUPP */
+#  ifdef EACCES
+#    define MHD_SCKT_EACCESS_     EACCES
+#  else  /* ! EACCES */
+#    define MHD_SCKT_EACCESS_     MHD_SCKT_MISSING_ERR_CODE_
+#  endif /* ! EACCES */
+#  ifdef ENETDOWN
+#    define MHD_SCKT_ENETDOWN_    ENETDOWN
+#  else  /* ! ENETDOWN */
+#    define MHD_SCKT_ENETDOWN_    MHD_SCKT_MISSING_ERR_CODE_
+#  endif /* ! ENETDOWN */
+#elif defined(MHD_WINSOCK_SOCKETS)
+#  define MHD_SCKT_EAGAIN_        WSAEWOULDBLOCK
+#  define MHD_SCKT_EWOULDBLOCK_   WSAEWOULDBLOCK
+#  define MHD_SCKT_EINTR_         WSAEINTR
+#  define MHD_SCKT_ECONNRESET_    WSAECONNRESET
+#  define MHD_SCKT_ECONNABORTED_  WSAECONNABORTED
+#  define MHD_SCKT_ENOTCONN_      WSAENOTCONN
+#  define MHD_SCKT_EMFILE_        WSAEMFILE
+#  define MHD_SCKT_ENFILE_        MHD_SCKT_MISSING_ERR_CODE_
+#  define MHD_SCKT_ENOMEM_        MHD_SCKT_MISSING_ERR_CODE_
+#  define MHD_SCKT_ENOBUFS_       WSAENOBUFS
+#  define MHD_SCKT_EBADF_         WSAEBADF
+#  define MHD_SCKT_ENOTSOCK_      WSAENOTSOCK
+#  define MHD_SCKT_EINVAL_        WSAEINVAL
+#  define MHD_SCKT_EFAUL_         WSAEFAULT
+#  define MHD_SCKT_ENOSYS_        MHD_SCKT_MISSING_ERR_CODE_
+#  define MHD_SCKT_ENOTSUP_       MHD_SCKT_MISSING_ERR_CODE_
+#  define MHD_SCKT_EOPNOTSUPP_    WSAEOPNOTSUPP
+#  define MHD_SCKT_EACCESS_       WSAEACCES
+#  define MHD_SCKT_ENETDOWN_      WSAENETDOWN
+#endif
+
+/**
+ * MHD_socket_error_ return system native error code for last socket error.
+ * @return system error code for last socket error.
+ */
+#if defined(MHD_POSIX_SOCKETS)
+#  define MHD_socket_get_error_() (errno)
+#elif defined(MHD_WINSOCK_SOCKETS)
+#  define MHD_socket_get_error_() WSAGetLastError()
+#endif
 
 #ifdef MHD_WINSOCK_SOCKETS
+  /* POSIX-W32 sockets compatibility functions */
 
-/* POSIX-W32 compatibility functions and macros */
+/**
+ * Return pointer to string description of specified WinSock error
+ * @param err the WinSock error code.
+ * @return pointer to string description of specified WinSock error.
+ */
+  const char* MHD_W32_strerror_winsock_(int err);
+#endif /* MHD_WINSOCK_SOCKETS */
 
-#  define MHDW32ERRBASE 3300
+/* MHD_socket_last_strerr_ is description string of specified socket error code */
+#if defined(MHD_POSIX_SOCKETS)
+#  define MHD_socket_strerr_(err) strerror((err))
+#elif defined(MHD_WINSOCK_SOCKETS)
+#  define MHD_socket_strerr_(err) MHD_W32_strerror_winsock_((err))
+#endif
 
-#  ifndef EWOULDBLOCK
-#    define EWOULDBLOCK (MHDW32ERRBASE+1)
-#  endif
-#  ifndef EINPROGRESS
-#    define EINPROGRESS (MHDW32ERRBASE+2)
-#  endif
-#  ifndef EALREADY
-#    define EALREADY (MHDW32ERRBASE+3)
-#  endif
-#  ifndef ENOTSOCK
-#    define ENOTSOCK (MHDW32ERRBASE+4)
-#  endif
-#  ifndef EDESTADDRREQ
-#    define EDESTADDRREQ (MHDW32ERRBASE+5)
-#  endif
-#  ifndef EMSGSIZE
-#    define EMSGSIZE (MHDW32ERRBASE+6)
-#  endif
-#  ifndef EPROTOTYPE
-#    define EPROTOTYPE (MHDW32ERRBASE+7)
-#  endif
-#  ifndef ENOPROTOOPT
-#    define ENOPROTOOPT (MHDW32ERRBASE+8)
-#  endif
-#  ifndef EPROTONOSUPPORT
-#    define EPROTONOSUPPORT (MHDW32ERRBASE+9)
-#  endif
-#  ifndef EOPNOTSUPP
-#    define EOPNOTSUPP (MHDW32ERRBASE+10)
-#  endif
-#  ifndef EAFNOSUPPORT
-#    define EAFNOSUPPORT (MHDW32ERRBASE+11)
-#  endif
-#  ifndef EADDRINUSE
-#    define EADDRINUSE (MHDW32ERRBASE+12)
-#  endif
-#  ifndef EADDRNOTAVAIL
-#    define EADDRNOTAVAIL (MHDW32ERRBASE+13)
-#  endif
-#  ifndef ENETDOWN
-#    define ENETDOWN (MHDW32ERRBASE+14)
-#  endif
-#  ifndef ENETUNREACH
-#    define ENETUNREACH (MHDW32ERRBASE+15)
-#  endif
-#  ifndef ENETRESET
-#    define ENETRESET (MHDW32ERRBASE+16)
-#  endif
-#  ifndef ECONNABORTED
-#    define ECONNABORTED (MHDW32ERRBASE+17)
-#  endif
-#  ifndef ECONNRESET
-#    define ECONNRESET (MHDW32ERRBASE+18)
-#  endif
-#  ifndef ENOBUFS
-#    define ENOBUFS (MHDW32ERRBASE+19)
-#  endif
-#  ifndef EISCONN
-#    define EISCONN (MHDW32ERRBASE+20)
-#  endif
-#  ifndef ENOTCONN
-#    define ENOTCONN (MHDW32ERRBASE+21)
-#  endif
-#  ifndef ETOOMANYREFS
-#    define ETOOMANYREFS (MHDW32ERRBASE+22)
-#  endif
-#  ifndef ECONNREFUSED
-#    define ECONNREFUSED (MHDW32ERRBASE+23)
-#  endif
-#  ifndef ELOOP
-#    define ELOOP (MHDW32ERRBASE+24)
-#  endif
-#  ifndef EHOSTDOWN
-#    define EHOSTDOWN (MHDW32ERRBASE+25)
-#  endif
-#  ifndef EHOSTUNREACH
-#    define EHOSTUNREACH (MHDW32ERRBASE+26)
-#  endif
-#  ifndef EPROCLIM
-#    define EPROCLIM (MHDW32ERRBASE+27)
-#  endif
-#  ifndef EUSERS
-#    define EUSERS (MHDW32ERRBASE+28)
-#  endif
-#  ifndef EDQUOT
-#    define EDQUOT (MHDW32ERRBASE+29)
-#  endif
-#  ifndef ESTALE
-#    define ESTALE (MHDW32ERRBASE+30)
-#  endif
-#  ifndef EREMOTE
-#    define EREMOTE (MHDW32ERRBASE+31)
-#  endif
-#  ifndef ESOCKTNOSUPPORT
-#    define ESOCKTNOSUPPORT (MHDW32ERRBASE+32)
-#  endif
-#  ifndef EPFNOSUPPORT
-#    define EPFNOSUPPORT (MHDW32ERRBASE+33)
-#  endif
-#  ifndef ESHUTDOWN
-#    define ESHUTDOWN (MHDW32ERRBASE+34)
-#  endif
-#  ifndef ENODATA
-#    define ENODATA (MHDW32ERRBASE+35)
-#  endif
-#  ifndef ETIMEDOUT
-#    define ETIMEDOUT (MHDW32ERRBASE+36)
-#  endif
+/* MHD_socket_last_strerr_ is description string of last errno (non-W32) /
+ *                            description string of last socket error (W32) */
+#define MHD_socket_last_strerr_() MHD_socket_strerr_(MHD_socket_get_error_())
 
 /**
- * Return errno equivalent of last winsock error
- * @return errno equivalent of last winsock error
+ * MHD_socket_fset_error_() set socket system native error code.
  */
-  int MHD_W32_errno_from_winsock_(void);
+#if defined(MHD_POSIX_SOCKETS)
+#  define MHD_socket_fset_error_(err) (errno = (err))
+#elif defined(MHD_WINSOCK_SOCKETS)
+#  define MHD_socket_fset_error_(err) (WSASetLastError((err)))
+#endif
 
 /**
- * Return pointer to string description of errnum error
- * Works fine with both standard errno errnums
- * and errnums from MHD_W32_errno_from_winsock_
- * @param errnum the errno or value from MHD_W32_errno_from_winsock_()
- * @return pointer to string description of error
+ * MHD_socket_try_set_error_() set socket system native error code if
+ * specified code is defined on system.
+ * @return non-zero if specified @a err code is defined on system
+ *         and error was set;
+ *         zero if specified @a err code is not defined on system
+ *         and error was not set.
  */
-  const char* MHD_W32_strerror_(int errnum);
+#define MHD_socket_try_set_error_(err) ( (MHD_SCKT_MISSING_ERR_CODE_ != (err)) ? \
+                                         (MHD_socket_fset_error_((err)), !0) : 0 )
 
 /**
- * Return pointer to string description of last winsock error
- * @return pointer to string description of last winsock error
+ * MHD_socket_set_error_() set socket system native error code to
+ * specified code or replacement code if specified code is not
+ * defined on system.
  */
-  const char* MHD_W32_strerror_last_winsock_(void);
+#if defined(MHD_POSIX_SOCKETS)
+#  if defined(ENOSYS)
+#    define MHD_socket_set_error_(err) ( (MHD_SCKT_MISSING_ERR_CODE_ == (err)) ? \
+                                         (errno = ENOSYS) : (errno = (err)) )
+#  elif defined(EOPNOTSUPP)
+#    define MHD_socket_set_error_(err) ( (MHD_SCKT_MISSING_ERR_CODE_ == (err)) ? \
+                                         (errno = EOPNOTSUPP) : (errno = (err)) )
+#  elif defined (EFAULT)
+#    define MHD_socket_set_error_(err) ( (MHD_SCKT_MISSING_ERR_CODE_ == (err)) ? \
+                                         (errno = EFAULT) : (errno = (err)) )
+#  elif defined (EINVAL)
+#    define MHD_socket_set_error_(err) ( (MHD_SCKT_MISSING_ERR_CODE_ == (err)) ? \
+                                         (errno = EINVAL) : (errno = (err)) )
+#  else  /* !EOPNOTSUPP && !EFAULT && !EINVAL */
+#    warning No suitable replacement for missing socket error code is found. Edit this file and add replacement code which is defined on system.
+#    define MHD_socket_set_error_(err) (errno = (err))
+#  endif /* !EOPNOTSUPP && !EFAULT && !EINVAL*/
+#elif defined(MHD_WINSOCK_SOCKETS)
+#  define MHD_socket_set_error_(err) ( (MHD_SCKT_MISSING_ERR_CODE_ == (err)) ? \
+                                       (WSASetLastError((WSAEOPNOTSUPP))) : \
+                                       (WSASetLastError((err))) )
+#endif
 
 /**
- * Set last winsock error to equivalent of given errno value
- * @param errnum the errno value to set
+ * Check whether given socket error is equal to specified system
+ * native MHD_SCKT_E*_ code.
+ * If platform don't have specific error code, result is
+ * always boolean false.
+ * @return boolean true if @a code is real error code and
+ *         @a err equals to MHD_SCKT_E*_ @a code;
+ *         boolean false otherwise
  */
-  void MHD_W32_set_last_winsock_error_(int errnum);
+#define MHD_SCKT_ERR_IS_(err,code) ( (MHD_SCKT_MISSING_ERR_CODE_ != (code)) && \
+                                     ((code) == (err)) )
 
+/**
+ * Check whether last socket error is equal to specified system
+ * native MHD_SCKT_E*_ code.
+ * If platform don't have specific error code, result is
+ * always boolean false.
+ * @return boolean true if @a code is real error code and
+ *         last socket error equals to MHD_SCKT_E*_ @a code;
+ *         boolean false otherwise
+ */
+#define MHD_SCKT_LAST_ERR_IS_(code) MHD_SCKT_ERR_IS_(MHD_socket_get_error_() ,(code))
 
-#endif /* MHD_WINSOCK_SOCKETS */
+/* Specific error code checks */
+
+/**
+ * Check whether given socket error is equal to system's
+ * socket error codes for EINTR.
+ * @return boolean true if @a err is equal to sockets' EINTR code;
+ *         boolean false otherwise.
+ */
+#define MHD_SCKT_ERR_IS_EINTR_(err) MHD_SCKT_ERR_IS_((err),MHD_SCKT_EINTR_)
+
+/**
+ * Check whether given socket error is equal to system's
+ * socket error codes for EAGAIN or EWOULDBLOCK.
+ * @return boolean true if @a err is equal to sockets' EAGAIN or EWOULDBLOCK codes;
+ *         boolean false otherwise.
+ */
+#if MHD_SCKT_EAGAIN_ == MHD_SCKT_EWOULDBLOCK_
+#  define MHD_SCKT_ERR_IS_EAGAIN_(err) MHD_SCKT_ERR_IS_((err),MHD_SCKT_EAGAIN_)
+#else  /* MHD_SCKT_EAGAIN_ != MHD_SCKT_EWOULDBLOCK_ */
+#  define MHD_SCKT_ERR_IS_EAGAIN_(err) ( MHD_SCKT_ERR_IS_((err),MHD_SCKT_EAGAIN_) || \
+                                         MHD_SCKT_ERR_IS_((err),MHD_SCKT_EWOULDBLOCK_) )
+#endif /* MHD_SCKT_EAGAIN_ != MHD_SCKT_EWOULDBLOCK_ */
+
+/**
+ * Check whether given socket error is any kind of "low resource" error.
+ * @return boolean true if @a err is any kind of "low resource" error,
+ *         boolean false otherwise.
+ */
+#define MHD_SCKT_ERR_IS_LOW_RESOURCES_(err) ( MHD_SCKT_ERR_IS_((err),MHD_SCKT_EMFILE_) || \
+                                              MHD_SCKT_ERR_IS_((err),MHD_SCKT_ENFILE_) || \
+                                              MHD_SCKT_ERR_IS_((err),MHD_SCKT_ENOMEM_) || \
+                                              MHD_SCKT_ERR_IS_((err),MHD_SCKT_ENOBUFS_) )
+
+/**
+ * Check whether is given socket error is type of "incoming connection
+ * was disconnected before 'accept()' is called".
+ * @return boolean true is @a err match described socket error code,
+ *         boolean false otherwise.
+ */
+#if defined(MHD_POSIX_SOCKETS)
+#  define MHD_SCKT_ERR_IS_DISCNN_BEFORE_ACCEPT_(err) MHD_SCKT_ERR_IS_((err),MHD_SCKT_ECONNABORTED_)
+#elif defined(MHD_WINSOCK_SOCKETS)
+#  define MHD_SCKT_ERR_IS_DISCNN_BEFORE_ACCEPT_(err) MHD_SCKT_ERR_IS_((err),MHD_SCKT_ECONNRESET_)
+#endif
+
+/**
+ * Check whether is given socket error is type of "connection was terminated
+ * by remote side".
+ * @return boolean true is @a err match described socket error code,
+ *         boolean false otherwise.
+ */
+#define MHD_SCKT_ERR_IS_REMOTE_DISCNN_(err) ( MHD_SCKT_ERR_IS_((err),MHD_SCKT_ECONNRESET_) || \
+                                              MHD_SCKT_ERR_IS_((err),MHD_SCKT_ECONNABORTED_))
+
+/* Specific error code set */
+
+/**
+ * Set socket's error code to ENOMEM or equivalent if ENOMEM is not
+ * available on platform.
+ */
+#if MHD_SCKT_MISSING_ERR_CODE_ != MHD_SCKT_ENOMEM_
+#  define MHD_socket_set_error_to_ENOMEM() MHD_socket_set_error_(MHD_SCKT_ENOMEM_)
+#elif MHD_SCKT_MISSING_ERR_CODE_ != MHD_SCKT_ENOBUFS_
+#  define MHD_socket_set_error_to_ENOMEM() MHD_socket_set_error_(MHD_SCKT_ENOBUFS_)
+#else
+#  warning No suitable replacement for ENOMEM error codes is found. Edit this file and add replacement code which is defined on system.
+#  define MHD_socket_set_error_to_ENOMEM() MHD_socket_set_error_(MHD_SCKT_ENOMEM_)
+#endif
 
 #endif /* ! MHD_SOCKETS_H */