mirror of
https://github.com/moparisthebest/curl
synced 2024-11-10 11:35:07 -05:00
54 lines
2.7 KiB
Groff
54 lines
2.7 KiB
Groff
.\"
|
|
.TH curl_multi_perform 3 "1 March 2002" "libcurl 7.9.5" "libcurl Manual"
|
|
.SH NAME
|
|
curl_multi_perform - reads/writes available data from each easy handle
|
|
.SH SYNOPSIS
|
|
#include <curl/curl.h>
|
|
|
|
CURLMcode curl_multi_perform(CURLM *multi_handle, int *running_handles);
|
|
.ad
|
|
.SH DESCRIPTION
|
|
When the app thinks there's data available for the multi_handle, it should
|
|
call this function to read/write whatever there is to read or write right
|
|
now. curl_multi_perform() returns as soon as the reads/writes are done. This
|
|
function does not require that there actually is any data available for
|
|
reading or that data can be written, it can be called just in case. It will
|
|
write the number of handles that still transfer data in the second argument's
|
|
integer-pointer.
|
|
|
|
When you call curl_multi_perform() and the amount of \fIrunning_handles\fP is
|
|
changed from the previous call (or is less than the amount of easy handles
|
|
you've added to the multi handle), you know that there is one or more
|
|
transfers less "running". You can then call \fIcurl_multi_info_read(3)\fP to
|
|
get information about each individual completed transfer, and that returned
|
|
info includes CURLcode and more. If an added handle fails very quickly, it may
|
|
never be counted as a running_handle.
|
|
|
|
When \fIrunning_handles\fP is set to zero (0) on the return of this function,
|
|
there is no longer any transfers in progress.
|
|
.SH "RETURN VALUE"
|
|
CURLMcode type, general libcurl multi interface error code.
|
|
|
|
Before version 7.20.0: If you receive \fICURLM_CALL_MULTI_PERFORM\fP, this
|
|
basically means that you should call \fIcurl_multi_perform\fP again, before
|
|
you select() on more actions. You don't have to do it immediately, but the
|
|
return code means that libcurl may have more data available to return or that
|
|
there may be more data to send off before it is "satisfied". Do note that
|
|
\fIcurl_multi_perform(3)\fP will return \fICURLM_CALL_MULTI_PERFORM\fP only
|
|
when it wants to be called again \fBimmediately\fP. When things are fine and
|
|
there is nothing immediate it wants done, it'll return \fICURLM_OK\fP and you
|
|
need to wait for \&"action" and then call this function again.
|
|
|
|
This function only returns errors etc regarding the whole multi stack.
|
|
Problems still might have occurred on individual transfers even when this
|
|
function returns \fICURLM_OK\fP.
|
|
.SH "TYPICAL USAGE"
|
|
Most applications will use \fIcurl_multi_fdset(3)\fP to get the multi_handle's
|
|
file descriptors, then it'll wait for action on them using \fBselect(3)\fP and
|
|
as soon as one or more of them are ready, \fIcurl_multi_perform(3)\fP gets
|
|
called.
|
|
.SH "SEE ALSO"
|
|
.BR curl_multi_cleanup "(3), " curl_multi_init "(3), "
|
|
.BR curl_multi_fdset "(3), " curl_multi_info_read "(3), "
|
|
.BR libcurl-errors "(3)"
|