x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
curl_multi_assign(3) libcurl curl_multi_assign(3)
NAME
curl_multi_assign - set data to associate with an internal socket
SYNOPSIS
#include <curl/curl.h>
CURLMcode curl_multi_assign(CURLM *multi_handle, curl_socket_t sockfd,
void *sockptr);
DESCRIPTION
This function creates an association in the multi handle between the
given socket and a private pointer of the application. This is designed
for curl_multi_socket_action(3) uses.
When set, the sockptr pointer is passed to all future socket callbacks
for the specific sockfd socket.
If the given sockfd is not already in use by libcurl, this function
returns an error.
libcurl only keeps one single pointer associated with a socket, so
calling this function several times for the same socket makes the last
set pointer get used.
The idea here being that this association (socket to private pointer)
is something that just about every application that uses this API needs
and then libcurl can just as well do it since it already has the neces-
sary functionality.
It is acceptable to call this function from your multi callback func-
tions.
EXAMPLE
/* make our struct pointer associated with socket fd */
mc = curl_multi_assign(multi_handle, fd, ourstructp);
AVAILABILITY
Added in 7.15.5
RETURN VALUE
The standard CURLMcode for multi interface error codes.
TYPICAL USAGE
In a typical application you allocate a struct or at least use some
kind of semi-dynamic data for each socket that we must wait for action
on when using the curl_multi_socket_action(3) approach.
When our socket-callback gets called by libcurl and we get to know
about yet another socket to wait for, we can use curl_multi_assign(3)
to point out the particular data so that when we get updates about this
same socket again, we do not have to find the struct associated with
this socket by ourselves.
SEE ALSO
curl_multi_setopt(3), curl_multi_socket_action(3)
libcurl 8.4.0 September 26, 2023 curl_multi_assign(3)
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