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Diffstat (limited to 'docs/libcurl/gnurl_multi_wait.3')
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1 files changed, 122 insertions, 0 deletions
diff --git a/docs/libcurl/gnurl_multi_wait.3 b/docs/libcurl/gnurl_multi_wait.3 new file mode 100644 index 000000000..d91481ab7 --- /dev/null +++ b/docs/libcurl/gnurl_multi_wait.3 @@ -0,0 +1,122 @@ +.\" ************************************************************************** +.\" * _ _ ____ _ +.\" * 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 gnurl_multi_wait 3 "12 Jul 2012" "libcurl 7.28.0" "libgnurl Manual" +.SH NAME +curl_multi_wait - polls on all easy handles in a multi handle +.SH SYNOPSIS +.nf +#include <gnurl/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)" |