curl_multi_assign(3) libcurl Manual curl_multi_assign(3)
NAME
curl_multi_assign - set data to associated 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 assigns an association in the multi handle between the given socket and a private
pointer of the application. This is (only) useful 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(3) approach.
When our socket-callback get 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 our-selves. ourselves.
selves.
AVAILABILITY
This function was added in libcurl 7.15.5, although not deemed stable yet.
SEE ALSO
curl_multi_setopt(3), curl_multi_socket(3)
libcurl 7.16.0 9 Jul 2006 curl_multi_assign(3)
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