docs/libcurl/opts/CURLOPT_CLOSESOCKETFUNCTION.3

.\" **************************************************************************
.\" *                                  _   _ ____  _
.\" *  Project                     ___| | | |  _ \| |
.\" *                             / __| | | | |_) | |
.\" *                            | (__| |_| |  _ <| |___
.\" *                             \___|\___/|_| \_\_____|
.\" *
.\" * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
.\" *
.\" * This software is licensed as described in the file COPYING, which
.\" * you should have received as part of this distribution. The terms
.\" * are also available at https://curl.se/docs/copyright.html.
.\" *
.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
.\" * copies of the Software, and permit persons to whom the Software is
.\" * furnished to do so, under the terms of the COPYING file.
.\" *
.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
.\" * KIND, either express or implied.
.\" *
.\" **************************************************************************
.\"
.TH CURLOPT_CLOSESOCKETFUNCTION 3 "November 04, 2020" "libcurl 7.78.0" "curl_easy_setopt options"

.SH NAME
CURLOPT_CLOSESOCKETFUNCTION \- callback to socket close replacement function
.SH SYNOPSIS
#include <curl/curl.h>

int closesocket_callback(void *clientp, curl_socket_t item);

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CLOSESOCKETFUNCTION, closesocket_callback);
.SH DESCRIPTION
Pass a pointer to your callback function, which should match the prototype
shown above.

This callback function gets called by libcurl instead of the \fIclose(3)\fP or
\fIclosesocket(3)\fP call when sockets are closed (not for any other file
descriptors). This is pretty much the reverse to the
\fICURLOPT_OPENSOCKETFUNCTION(3)\fP option. Return 0 to signal success and 1
if there was an error.

The \fIclientp\fP pointer is set with
\fICURLOPT_CLOSESOCKETDATA(3)\fP. \fIitem\fP is the socket libcurl wants to be
closed.
.SH DEFAULT
By default libcurl uses the standard socket close function.
.SH PROTOCOLS
All
.SH EXAMPLE
.nf
static int closesocket(void *clientp, curl_socket_t item)
{
  printf("libcurl wants to close %d now\\n", (int)item);
  return 0;
}

/* call this function to close sockets */
curl_easy_setopt(curl, CURLOPT_CLOSESOCKETFUNCTION, closesocket);
curl_easy_setopt(curl, CURLOPT_CLOSESOCKETDATA, &sockfd);
.fi
.SH AVAILABILITY
Added in 7.21.7
.SH RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
.SH "SEE ALSO"
.BR CURLOPT_CLOSESOCKETDATA "(3), " CURLOPT_OPENSOCKETFUNCTION "(3), "