1---
2c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
3SPDX-License-Identifier: curl
4Title: curl_multi_socket
5Section: 3
6Source: libcurl
7See-also:
8  - curl_multi_cleanup (3)
9  - curl_multi_fdset (3)
10  - curl_multi_info_read (3)
11  - curl_multi_init (3)
12  - the hiperfifo.c example
13Protocol:
14  - All
15---
16
17# NAME
18
19curl_multi_socket - reads/writes available data
20
21# SYNOPSIS
22
23~~~c
24#include <curl/curl.h>
25CURLMcode curl_multi_socket(CURLM *multi_handle, curl_socket_t sockfd,
26                            int *running_handles);
27
28CURLMcode curl_multi_socket_all(CURLM *multi_handle,
29                                int *running_handles);
30~~~
31
32# DESCRIPTION
33
34These functions are deprecated. Do not use. See
35curl_multi_socket_action(3) instead.
36
37At return, the integer **running_handles** points to contains the number of
38still running easy handles within the multi handle. When this number reaches
39zero, all transfers are complete/done. Note that when you call
40curl_multi_socket_action(3) on a specific socket and the counter
41decreases by one, it DOES NOT necessarily mean that this exact socket/transfer
42is the one that completed. Use curl_multi_info_read(3) to figure out
43which easy handle that completed.
44
45The curl_multi_socket_action(3) functions inform the application about
46updates in the socket (file descriptor) status by doing none, one, or multiple
47calls to the socket callback function set with the
48CURLMOPT_SOCKETFUNCTION(3) option to curl_multi_setopt(3). They
49update the status with changes since the previous time the callback was
50called.
51
52Get the timeout time by setting the CURLMOPT_TIMERFUNCTION(3) option
53with curl_multi_setopt(3). Your application then gets called with
54information on how long to wait for socket actions at most before doing the
55timeout action: call the curl_multi_socket_action(3) function with the
56**sockfd** argument set to CURL_SOCKET_TIMEOUT. You can also use the
57curl_multi_timeout(3) function to poll the value at any given time, but
58for an event-based system using the callback is far better than relying on
59polling the timeout value.
60
61Usage of curl_multi_socket(3) is deprecated, whereas the function is
62equivalent to curl_multi_socket_action(3) with **ev_bitmask** set to
630.
64
65Force libcurl to (re-)check all its internal sockets and transfers instead of
66just a single one by calling curl_multi_socket_all(3). Note that there
67should not be any reason to use this function.
68
69# EXAMPLE
70
71~~~c
72int main(void)
73{
74  /* the event-library gets told when there activity on the socket 'fd',
75     which we translate to a call to curl_multi_socket_action() */
76  int running;
77  int rc;
78  int fd;
79  CURLM *multi;
80  rc = curl_multi_socket(multi, fd, &running);
81}
82~~~
83
84# AVAILABILITY
85
86This function was added in libcurl 7.15.4, and is deemed stable since
877.16.0.
88
89curl_multi_socket(3) is deprecated, use
90curl_multi_socket_action(3) instead!
91
92# RETURN VALUE
93
94CURLMcode type, general libcurl multi interface error code.
95
96The return code is for the whole multi stack. Problems still might have
97occurred on individual transfers even when one of these functions return OK.
98