curl/docs/libcurl/curl_multi_timeout.3

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.TH curl_multi_timeout 3 "2 Jan 2006" "libcurl 7.16.0" "libcurl Manual"
.SH NAME
curl_multi_timeout \- how long to wait for action before proceeding
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLMcode curl_multi_timeout(CURLM *multi_handle, long *timeout);
.fi
.SH DESCRIPTION

An application using the libcurl multi interface should call
\fIcurl_multi_timeout(3)\fP to figure out how long it should wait for socket
actions \- at most \- before proceeding.

Proceeding means either doing the socket-style timeout action: call the
\fIcurl_multi_socket_action(3)\fP function with the \fBsockfd\fP argument set
to CURL_SOCKET_TIMEOUT, or call \fIcurl_multi_perform(3)\fP if you are using
the simpler and older multi interface approach.

The timeout value returned in the long \fBtimeout\fP points to, is in number
of milliseconds at this moment. If 0, it means you should proceed immediately
without waiting for anything. If it returns -1, there's no timeout at all set.

An application that uses the multi_socket API SHOULD NOT use this function,
but SHOULD instead use the \fICURLMOPT_TIMERFUNCTION(3)\fP option for proper
and desired behavior.

Note: if libcurl returns a -1 timeout here, it just means that libcurl
currently has no stored timeout value. You must not wait too long (more than a
few seconds perhaps) before you call curl_multi_perform() again.
.SH EXAMPLE
.nf
struct timeval timeout;
long timeo;

curl_multi_timeout(multi_handle, &timeo);
if(timeo < 0)
  /* no set timeout, use a default */
  timeo = 980;

timeout.tv_sec = timeo / 1000;
timeout.tv_usec = (timeo % 1000) * 1000;

/* wait for activities no longer than the set timeout */
select(maxfd+1, &fdread, &fdwrite, &fdexcep, &timeout);
.fi
.SH TYPICAL USAGE
Call \fIcurl_multi_timeout(3)\fP, then wait for action on the sockets. Figure
out which sockets to wait for by calling \fIcurl_multi_fdset(3)\fP.

When there is activity or timeout, call \fIcurl_multi_perform(3)\fP and then
loop - until all transfers are complete.
.SH AVAILABILITY
This function was added in libcurl 7.15.4.
.SH RETURN VALUE
The standard CURLMcode for multi interface error codes.
.SH "SEE ALSO"
.BR curl_multi_fdset "(3), " curl_multi_info_read "(3), "
.BR curl_multi_socket "(3), " curl_multi_setopt "(3) "