1---
2c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
3SPDX-License-Identifier: curl
4Title: CURLOPT_CLOSESOCKETFUNCTION
5Section: 3
6Source: libcurl
7See-also:
8  - CURLOPT_CLOSESOCKETDATA (3)
9  - CURLOPT_OPENSOCKETFUNCTION (3)
10Protocol:
11  - All
12---
13
14# NAME
15
16CURLOPT_CLOSESOCKETFUNCTION - callback to socket close replacement
17
18# SYNOPSIS
19
20~~~c
21#include <curl/curl.h>
22
23int closesocket_callback(void *clientp, curl_socket_t item);
24
25CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CLOSESOCKETFUNCTION,
26                          closesocket_callback);
27~~~
28
29# DESCRIPTION
30
31Pass a pointer to your callback function, which should match the prototype
32shown above.
33
34This callback function gets called by libcurl instead of the *close(3)* or
35*closesocket(3)* call when sockets are closed (not for any other file
36descriptors). This is pretty much the reverse to the
37CURLOPT_OPENSOCKETFUNCTION(3) option. Return 0 to signal success and 1
38if there was an error.
39
40The *clientp* pointer is set with
41CURLOPT_CLOSESOCKETDATA(3). *item* is the socket libcurl wants to be
42closed.
43
44# DEFAULT
45
46By default libcurl uses the standard socket close function.
47
48# EXAMPLE
49
50~~~c
51struct priv {
52  void *custom;
53};
54
55static int closesocket(void *clientp, curl_socket_t item)
56{
57  struct priv *my = clientp;
58  printf("our ptr: %p\n", my->custom);
59
60  printf("libcurl wants to close %d now\n", (int)item);
61  return 0;
62}
63
64int main(void)
65{
66  struct priv myown;
67  CURL *curl = curl_easy_init();
68
69  /* call this function to close sockets */
70  curl_easy_setopt(curl, CURLOPT_CLOSESOCKETFUNCTION, closesocket);
71  curl_easy_setopt(curl, CURLOPT_CLOSESOCKETDATA, &myown);
72
73  curl_easy_perform(curl);
74  curl_easy_cleanup(curl);
75}
76~~~
77
78# AVAILABILITY
79
80Added in 7.21.7
81
82# RETURN VALUE
83
84Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
85