curl/docs/libcurl/opts/CURLOPT_CONNECT_ONLY.3

.\" **************************************************************************
.\" *                                  _   _ ____  _
.\" *  Project                     ___| | | |  _ \| |
.\" *                             / __| | | | |_) | |
.\" *                            | (__| |_| |  _ <| |___
.\" *                             \___|\___/|_| \_\_____|
.\" *
.\" * Copyright (C) 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.
.\" *
.\" * SPDX-License-Identifier: curl
.\" *
.\" **************************************************************************
.\"
.TH CURLOPT_CONNECT_ONLY 3 "19 Jun 2014" libcurl libcurl
.SH NAME
CURLOPT_CONNECT_ONLY \- stop when connected to target server
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CONNECT_ONLY, long only);
.fi
.SH DESCRIPTION
Pass a long. If the parameter equals 1, it tells the library to perform all
the required proxy authentication and connection setup, but no data transfer,
and then return.

The option can be used to simply test a connection to a server, but is more
useful when used with the \fICURLINFO_ACTIVESOCKET(3)\fP option to
\fIcurl_easy_getinfo(3)\fP as the library can set up the connection and then
the application can obtain the most recently used socket for special data
transfers.

Since 7.86.0, this option can be set to '2' and if HTTP or WebSocket are
used, libcurl will do the request and read all response headers before handing
over control to the application.

Transfers marked connect only will not reuse any existing connections and
connections marked connect only will not be allowed to get reused.

If the connect only transfer is done using the multi interface, the particular
easy handle must remain added to the multi handle for as long as the
application wants to use it. Once it has been removed with
\fIcurl_multi_remove_handle(3)\fP, \fIcurl_easy_send(3)\fP and
\fIcurl_easy_recv(3)\fP do not function.
.SH DEFAULT
0
.SH PROTOCOLS
HTTP, SMTP, POP3 and IMAP. For WS and WSS starting in 7.86.0.
.SH EXAMPLE
.nf
CURL *curl = curl_easy_init();
if(curl) {
  CURLcode ret;
  curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
  curl_easy_setopt(curl, CURLOPT_CONNECT_ONLY, 1L);
  ret = curl_easy_perform(curl);
  if(ret == CURLE_OK) {
    /* only connected! */
  }
}
.fi
.SH AVAILABILITY
Added in 7.15.2
.SH RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
.SH "SEE ALSO"
.BR CURLOPT_VERBOSE "(3), " CURLOPT_HTTPPROXYTUNNEL  "(3), "
.BR curl_easy_recv "(3), " curl_easy_send "(3) "