curl_multi_assign(3)						  libcurl Manual					      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 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)

libcurl 7.54.0							 February 03, 2016					      curl_multi_assign(3)