curl_multi_fdset.3
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- ." $Id: curl_multi_fdset.3,v 1.13 2008-12-28 21:56:56 bagder Exp $
- ."
- .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 no file descriptors are set by libcurl, fImax_fdfP will contain -1 when
- this function returns. Otherwise it will contain the higher descriptor number
- libcurl set.
- 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_performfP 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.
- Starting with libcurl 7.16.0, you should use fBcurl_multi_timeoutfP to
- figure out how long to wait for action.
- .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_timeout "(3) "