123 lines
4.3 KiB
Groff
123 lines
4.3 KiB
Groff
.\" **************************************************************************
|
|
.\" * _ _ ____ _
|
|
.\" * Project ___| | | | _ \| |
|
|
.\" * / __| | | | |_) | |
|
|
.\" * | (__| |_| | _ <| |___
|
|
.\" * \___|\___/|_| \_\_____|
|
|
.\" *
|
|
.\" * Copyright (C) 1998 - 2016, 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_wait 3 "12 Jul 2012" "libcurl 7.28.0" "libcurl Manual"
|
|
.SH NAME
|
|
curl_multi_wait - polls on all easy handles in a multi handle
|
|
.SH SYNOPSIS
|
|
.nf
|
|
#include <curl/curl.h>
|
|
|
|
CURLMcode curl_multi_wait(CURLM *multi_handle,
|
|
struct curl_waitfd extra_fds[],
|
|
unsigned int extra_nfds,
|
|
int timeout_ms,
|
|
int *numfds);
|
|
.ad
|
|
.SH DESCRIPTION
|
|
\fIcurl_multi_wait(3)\fP polls all file descriptors used by the curl easy
|
|
handles contained in the given multi handle set. It will block until activity
|
|
is detected on at least one of the handles or \fItimeout_ms\fP has passed.
|
|
Alternatively, if the multi handle has a pending internal timeout that has a
|
|
shorter expiry time than \fItimeout_ms\fP, that shorter time will be used
|
|
instead to make sure timeout accuracy is reasonably kept.
|
|
|
|
The calling application may pass additional curl_waitfd structures which are
|
|
similar to \fIpoll(2)\fP's pollfd structure to be waited on in the same call.
|
|
|
|
On completion, if \fInumfds\fP is non-NULL, it will be populated with the
|
|
total number of file descriptors on which interesting events occurred. This
|
|
number can include both libcurl internal descriptors as well as descriptors
|
|
provided in \fIextra_fds\fP.
|
|
|
|
If no extra file descriptors are provided and libcurl has no file descriptor
|
|
to offer to wait for, this function will return immediately.
|
|
|
|
This function is encouraged to be used instead of select(3) when using the
|
|
multi interface to allow applications to easier circumvent the common problem
|
|
with 1024 maximum file descriptors.
|
|
.SH curl_waitfd
|
|
.nf
|
|
struct curl_waitfd {
|
|
curl_socket_t fd;
|
|
short events;
|
|
short revents;
|
|
};
|
|
.fi
|
|
.IP CURL_WAIT_POLLIN
|
|
Bit flag to curl_waitfd.events indicating the socket should poll on read
|
|
events such as new data received.
|
|
.IP CURL_WAIT_POLLPRI
|
|
Bit flag to curl_waitfd.events indicating the socket should poll on high
|
|
priority read events such as out of band data.
|
|
.IP CURL_WAIT_POLLOUT
|
|
Bit flag to curl_waitfd.events indicating the socket should poll on write
|
|
events such as the socket being clear to write without blocking.
|
|
.SH EXAMPLE
|
|
.nf
|
|
CURL *easy_handle;
|
|
CURLM *multi_handle;
|
|
|
|
/* add the individual easy handle */
|
|
curl_multi_add_handle(multi_handle, easy_handle);
|
|
|
|
do {
|
|
CURLMcode mc;
|
|
int numfds;
|
|
|
|
mc = curl_multi_perform(multi_handle, &still_running);
|
|
|
|
if(mc == CURLM_OK ) {
|
|
/* wait for activity, timeout or "nothing" */
|
|
mc = curl_multi_wait(multi_handle, NULL, 0, 1000, &numfds);
|
|
}
|
|
|
|
if(mc != CURLM_OK) {
|
|
fprintf(stderr, "curl_multi failed, code %d.\n", mc);
|
|
break;
|
|
}
|
|
|
|
/* 'numfds' being zero means either a timeout or no file descriptors to
|
|
wait for. Try timeout on first occurrence, then assume no file
|
|
descriptors and no file descriptors to wait for means wait for 100
|
|
milliseconds. */
|
|
|
|
if(!numfds) {
|
|
repeats++; /* count number of repeated zero numfds */
|
|
if(repeats > 1) {
|
|
WAITMS(100); /* sleep 100 milliseconds */
|
|
}
|
|
}
|
|
else
|
|
repeats = 0;
|
|
|
|
} while(still_running);
|
|
|
|
curl_multi_remove_handle(multi_handle, easy_handle);
|
|
.fi
|
|
.SH RETURN VALUE
|
|
CURLMcode type, general libcurl multi interface error code. See
|
|
\fIlibcurl-errors(3)\fP
|
|
.SH AVAILABILITY
|
|
This function was added in libcurl 7.28.0.
|
|
.SH "SEE ALSO"
|
|
.BR curl_multi_fdset "(3), " curl_multi_perform "(3)"
|