NAME¶
curl_multi_assign - set data to association 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(3) uses.
When set, the
sockptr pointer will be passed to all future socket
callbacks for the specific
sockfd socket.
If the given
sockfd isn't already in use by libcurl, this function will
return an error.
libcurl only keeps one single pointer associated with a socket, so calling this
function several times for the same socket will make 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 will need and
then libcurl can just as well do it since it already has an internal hash
table lookup for this.
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 don't have to find the struct associated with this socket by
ourselves.
AVAILABILITY¶
This function was added in libcurl 7.15.5.
SEE ALSO¶
curl_multi_setopt(3),
curl_multi_socket_action(3)