.\" **************************************************************************
.\" *                                  _   _ ____  _
.\" *  Project                     ___| | | |  _ \| |
.\" *                             / __| | | | |_) | |
.\" *                            | (__| |_| |  _ <| |___
.\" *                             \___|\___/|_| \_\_____|
.\" *
.\" * Copyright (C) 1998 - 2019, 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.haxx.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_HEADEROPT 3 "October 31, 2019" "libcurl 7.73.0" "curl_easy_setopt options"

.SH NAME
CURLOPT_HEADEROPT \- set how to send HTTP headers
.SH SYNOPSIS
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HEADEROPT, long bitmask);
.SH DESCRIPTION
Pass a long that is a bitmask of options of how to deal with headers. The two
mutually exclusive options are:

\fBCURLHEADER_UNIFIED\fP - the headers specified in
\fICURLOPT_HTTPHEADER(3)\fP will be used in requests both to servers and
proxies. With this option enabled, \fICURLOPT_PROXYHEADER(3)\fP will not have
any effect.

\fBCURLHEADER_SEPARATE\fP - makes \fICURLOPT_HTTPHEADER(3)\fP headers only get
sent to a server and not to a proxy. Proxy headers must be set with
\fICURLOPT_PROXYHEADER(3)\fP to get used. Note that if a non-CONNECT request
is sent to a proxy, libcurl will send both server headers and proxy
headers. When doing CONNECT, libcurl will send \fICURLOPT_PROXYHEADER(3)\fP
headers only to the proxy and then \fICURLOPT_HTTPHEADER(3)\fP headers only to
the server.
.SH DEFAULT
CURLHEADER_SEPARATE (changed in 7.42.1, used CURLHEADER_UNIFIED before then)
.SH PROTOCOLS
HTTP
.SH EXAMPLE
.nf
CURL *curl = curl_easy_init();
if(curl) {
  CURLcode ret;
  struct curl_slist *list;
  list = curl_slist_append(NULL, "Shoesize: 10");
  list = curl_slist_append(list, "Accept:");
  curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
  curl_easy_setopt(curl, CURLOPT_PROXY, "http://localhost:8080");
  curl_easy_setopt(curl, CURLOPT_HTTPHEADER, list);

  /* HTTPS over a proxy makes a separate CONNECT to the proxy, so tell
     libcurl to not send the custom headers to the proxy. Keep them
     separate! */
  curl_easy_setopt(curl, CURLOPT_HEADEROPT, CURLHEADER_SEPARATE);
  ret = curl_easy_perform(curl);
  curl_slist_free_all(list);
  curl_easy_cleanup(curl);
}
.fi
.SH AVAILABILITY
Added in 7.37.0
.SH RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
.SH "SEE ALSO"
.BR CURLOPT_HTTPHEADER "(3), " CURLOPT_PROXYHEADER "(3), "