82 lines
2.3 KiB
Markdown
82 lines
2.3 KiB
Markdown
|
---
|
||
|
|
c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
|
||
|
|
SPDX-License-Identifier: curl
|
||
|
|
Title: curl_multi_assign
|
||
|
|
Section: 3
|
||
|
|
Source: libcurl
|
||
|
|
See-also:
|
||
|
|
- curl_multi_setopt (3)
|
||
|
|
- curl_multi_socket_action (3)
|
||
|
|
---
|
||
|
|
|
||
|
|
# NAME
|
||
|
|
|
||
|
|
curl_multi_assign - set data to associate with an internal socket
|
||
|
|
|
||
|
|
# SYNOPSIS
|
||
|
|
|
||
|
|
~~~c
|
||
|
|
#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 necessary
|
||
|
|
functionality.
|
||
|
|
|
||
|
|
It is acceptable to call this function from your multi callback functions.
|
||
|
|
|
||
|
|
# EXAMPLE
|
||
|
|
|
||
|
|
~~~c
|
||
|
|
int main(void)
|
||
|
|
{
|
||
|
|
CURLM *multi = curl_multi_init();
|
||
|
|
void *ourstructp; /* pointer to our data */
|
||
|
|
curl_socket_t fd; /* file descriptor to associate our data with */
|
||
|
|
|
||
|
|
/* make our struct pointer associated with socket fd */
|
||
|
|
CURLMcode mc = curl_multi_assign(multi, fd, ourstructp);
|
||
|
|
if(mc)
|
||
|
|
printf("error: %s\n", curl_multi_strerror(mc));
|
||
|
|
}
|
||
|
|
~~~
|
||
|
|
|
||
|
|
# 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.
|