3 files changed, 47 insertions, 20 deletions

diff --git a/doc/libmicrohttpd.texi b/doc/libmicrohttpd.texi
index dba1d08f..82d9f415 100644
--- a/doc/libmicrohttpd.texi
+++ b/doc/libmicrohttpd.texi
@@ -1594,6 +1594,15 @@ is added to @var{read_fd_set}. The list of currently existent
 connections is scanned and their file descriptors added to the correct
 set.
 
+When calling this function, FD_SETSIZE is assumed to be platform's
+default.  If you changed FD_SETSIZE for your application,
+you should use @code{MHD_get_fdset2()} instead.
+
+This function should only be called in when MHD is configured to use
+external select with @code{select()} or with @code{epoll()}.  In
+the latter case, it will only add the single @code{epoll()} file
+descriptor used by MHD to the sets.
+
 After the call completed successfully: the variable referenced by
 @var{max_fd} references the file descriptor with highest integer
 identifier. The variable must be set to zero before invoking this
@@ -1605,6 +1614,10 @@ the right options for this call.
 @end deftypefun
 
 
+@deftypefun int MHD_get_fdset2 (struct MHD_Daemon *daemon, fd_set * read_fd_set, fd_set * write_fd_set, fd_set * except_fd_set, int *max_fd, unsigned int fd_setsize)
+Like @code{MHD_get_fdset()}, except that you can manually specify the value of FD_SETSIZE used by your application.
+
+
 @deftypefun int MHD_get_timeout (struct MHD_Daemon *daemon, unsigned long long *timeout)
 @cindex timeout
 Obtain timeout value for select for this daemon (only needed if
diff --git a/src/include/microhttpd.h b/src/include/microhttpd.h
index a09cddf3..40545452 100644
--- a/src/include/microhttpd.h
+++ b/src/include/microhttpd.h
@@ -2178,8 +2178,13 @@ MHD_add_connection (struct MHD_Daemon *daemon,
  * before calling this function. FD_SETSIZE is assumed
  * to be platform's default.
  *
- * This function could be called only for daemon started
- * without MHD_USE_INTERNAL_POLLING_THREAD flag.
+ * This function should only be called in when MHD is configured to
+ * use external select with @code{select()} or with @code{epoll()}.
+ * In the latter case, it will only add the single @code{epoll()} file
+ * descriptor used by MHD to the sets.
+ *
+ * This function must be called only for daemon started
+ * without #MHD_USE_INTERNAL_POLLING_THREAD flag.
  *
  * @param daemon daemon to get sets from
  * @param read_fd_set read set
@@ -2205,12 +2210,18 @@ MHD_get_fdset (struct MHD_Daemon *daemon,
  * Obtain the `select()` sets for this daemon.
  * Daemon's FDs will be added to fd_sets. To get only
  * daemon FDs in fd_sets, call FD_ZERO for each fd_set
- * before calling this function. Passing custom FD_SETSIZE
- * as @a fd_setsize allow usage of larger/smaller than
- * platform's default fd_sets.
+ * before calling this function.
  *
- * This function could be called only for daemon started
- * without MHD_USE_INTERNAL_POLLING_THREAD flag.
+ * Passing custom FD_SETSIZE as @a fd_setsize allow usage of
+ * larger/smaller than platform's default fd_sets.
+ *
+ * This function should only be called in when MHD is configured to
+ * use external select with @code{select()} or with @code{epoll()}.
+ * In the latter case, it will only add the single @code{epoll()} file
+ * descriptor used by MHD to the sets.
+ *
+ * This function must be called only for daemon started
+ * without #MHD_USE_INTERNAL_POLLING_THREAD flag.
  *
  * @param daemon daemon to get sets from
  * @param read_fd_set read set
@@ -2227,11 +2238,11 @@ MHD_get_fdset (struct MHD_Daemon *daemon,
  */
 _MHD_EXTERN int
 MHD_get_fdset2 (struct MHD_Daemon *daemon,
-               fd_set *read_fd_set,
-               fd_set *write_fd_set,
-               fd_set *except_fd_set,
-               MHD_socket *max_fd,
-               unsigned int fd_setsize);
+                fd_set *read_fd_set,
+                fd_set *write_fd_set,
+                fd_set *except_fd_set,
+                MHD_socket *max_fd,
+                unsigned int fd_setsize);
 
 
 /**
@@ -2242,7 +2253,7 @@ MHD_get_fdset2 (struct MHD_Daemon *daemon,
  * determined by current value of FD_SETSIZE.
  *
  * This function could be called only for daemon started
- * without MHD_USE_INTERNAL_POLLING_THREAD flag.
+ * without #MHD_USE_INTERNAL_POLLING_THREAD flag.
  *
  * @param daemon daemon to get sets from
  * @param read_fd_set read set
@@ -2288,7 +2299,7 @@ MHD_get_timeout (struct MHD_Daemon *daemon,
  * fd_sets from #MHD_get_fdset were not directly passed to `select()`;
  * with this function, MHD will internally do the appropriate `select()`
  * call itself again.  While it is always safe to call #MHD_run (if
- * ::MHD_USE_INTERNAL_POLLING_THREAD is not set), you should call
+ * #MHD_USE_INTERNAL_POLLING_THREAD is not set), you should call
  * #MHD_run_from_select if performance is important (as it saves an
  * expensive call to `select()`).
  *
@@ -2315,7 +2326,7 @@ MHD_run (struct MHD_Daemon *daemon);
  * ready.
  *
  * This function cannot be used with daemon started with
- * MHD_USE_INTERNAL_POLLING_THREAD flag.
+ * #MHD_USE_INTERNAL_POLLING_THREAD flag.
  *
  * @param daemon daemon to run select loop for
  * @param read_fd_set read set
diff --git a/src/microhttpd/daemon.c b/src/microhttpd/daemon.c
index 991577b1..d1ec032a 100644
--- a/src/microhttpd/daemon.c
+++ b/src/microhttpd/daemon.c
@@ -1046,8 +1046,8 @@ internal_get_fdset2 (struct MHD_Daemon *daemon,
  * as @a fd_setsize allow usage of larger/smaller than
  * platform's default fd_sets.
  *
- * This function could be called only for daemon started
- * without MHD_USE_INTERNAL_POLLING_THREAD flag.
+ * This function must be called only for daemon started
+ * without #MHD_USE_INTERNAL_POLLING_THREAD flag.
  *
  * @param daemon daemon to get sets from
  * @param read_fd_set read set
@@ -1106,9 +1106,12 @@ MHD_get_fdset2 (struct MHD_Daemon *daemon,
     }
 #endif
 
-  return internal_get_fdset2 (daemon, read_fd_set,
-                              write_fd_set, except_fd_set,
-                              max_fd, fd_setsize);
+  return internal_get_fdset2 (daemon,
+                              read_fd_set,
+                              write_fd_set,
+                              except_fd_set,
+                              max_fd,
+                              fd_setsize);
 }