curl/docs/libcurl/curl_multi_fdset.3

.\" $Id$
.\"
.TH curl_multi_fdset 3 "18 Apr 2005" "libcurl 7.9.5" "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 other. The \fIcurl_multi_perform(3)\fP function should be
called as soon as one of them are ready to be read from or written to.

You should also be aware that when doing select(), you should consider using a
rather small (single-digit number of seconds) timeout and call
\fIcurl_multi_perform\fP regularly - even if no activity has been seen on the
fd_sets - as otherwise libcurl-internal retries and timeouts may not work as
you'd think and want.
.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)"