--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/curl/docs/libcurl/curl_multi_fdset.3	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,84 @@
+.\" **************************************************************************
+.\" *                                  _   _ ____  _
+.\" *  Project                     ___| | | |  _ \| |
+.\" *                             / __| | | | |_) | |
+.\" *                            | (__| |_| |  _ <| |___
+.\" *                             \___|\___/|_| \_\_____|
+.\" *
+.\" * Copyright (C) 1998 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
+.\" *
+.\" * This software is licensed as described in the file COPYING, which
+.\" * you should have received as part of this distribution. The terms
+.\" * are also available at https://curl.haxx.se/docs/copyright.html.
+.\" *
+.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+.\" * copies of the Software, and permit persons to whom the Software is
+.\" * furnished to do so, under the terms of the COPYING file.
+.\" *
+.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+.\" * KIND, either express or implied.
+.\" *
+.\" **************************************************************************
+.TH curl_multi_fdset 3 "2 Jan 2006" "libcurl 7.16.0" "libcurl Manual"
+.SH NAME
+curl_multi_fdset - extracts file descriptor information from a multi handle
+.SH SYNOPSIS
+.nf
+#include <curl/curl.h>
+
+CURLMcode curl_multi_fdset(CURLM *multi_handle,
+                           fd_set *read_fd_set,
+                           fd_set *write_fd_set,
+                           fd_set *exc_fd_set,
+                           int *max_fd);
+.ad
+.SH DESCRIPTION
+This function extracts file descriptor information from a given multi_handle.
+libcurl returns its fd_set sets. The application can use these to select() on,
+but be sure to FD_ZERO them before calling this function as
+\fIcurl_multi_fdset(3)\fP only adds its own descriptors, it doesn't zero or
+otherwise remove any others. The \fIcurl_multi_perform(3)\fP function should
+be called as soon as one of them is ready to be read from or written to.
+
+If the \fIread_fd_set\fP argument is not a null pointer, it points to an
+object of type fd_set that on returns specifies the file descriptors to be
+checked for being ready to read.
+
+If the \fIwrite_fd_set\fP argument is not a null pointer, it points to an
+object of type fd_set that on return specifies the file descriptors to be
+checked for being ready to write.
+
+If the \fIexc_fd_set\fP argument is not a null pointer, it points to an object
+of type fd_set that on return specifies the file descriptors to be checked for
+error conditions pending.
+
+If no file descriptors are set by libcurl, \fImax_fd\fP will contain -1 when
+this function returns. Otherwise it will contain the highest descriptor number
+libcurl set. When libcurl returns -1 in \fImax_fd\fP, it is because libcurl
+currently does something that isn't possible for your application to monitor
+with a socket and unfortunately you can then not know exactly when the current
+action is completed using select(). You then need to wait a while before you
+proceed and call \fIcurl_multi_perform(3)\fP anyway. How long to wait? Unless
+\fIcurl_multi_timeout(3)\fP gives you a lower number, we suggest 100
+milliseconds or so, but you may want to test it out in your own particular
+conditions to find a suitable value.
+
+When doing select(), you should use \fIcurl_multi_timeout(3)\fP to figure out
+how long to wait for action. Call \fIcurl_multi_perform(3)\fP even if no
+activity has been seen on the fd_sets after the timeout expires as otherwise
+internal retries and timeouts may not work as you'd think and want.
+
+If one of the sockets used by libcurl happens to be larger than what can be
+set in an fd_set, which on POSIX systems means that the file descriptor is
+larger than FD_SETSIZE, then libcurl will try to not set it. Setting a too
+large file descriptor in an fd_set implies an out of bounds write which can
+cause crashes, or worse. The effect of NOT storing it will possibly save you
+from the crash, but will make your program NOT wait for sockets it should wait
+for...
+.SH RETURN VALUE
+CURLMcode type, general libcurl multi interface error code. See
+\fIlibcurl-errors(3)\fP
+.SH "SEE ALSO"
+.BR curl_multi_cleanup "(3), " curl_multi_init "(3), "
+.BR curl_multi_wait "(3), "
+.BR curl_multi_timeout "(3), " curl_multi_perform "(3), " select "(2) "