CURLOPT_HEADEROPT(3)       curl_easy_setopt options       CURLOPT_HEADEROPT(3)

NAME
       CURLOPT_HEADEROPT - set how to send HTTP headers

SYNOPSIS
       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HEADEROPT, long
       bitmask);

DESCRIPTION
       Pass a long that is a bitmask of options of how to deal with headers.
       The two mutually exclusive options are:

       CURLHEADER_UNIFIED - the headers specified in _HTTPHEADER&section=3">CURLOPT_HTTPHEADER(3)
       will be used in requests both to servers and proxies. With this option
       enabled, _PROXYHEADER&section=3">CURLOPT_PROXYHEADER(3) will not have any effect.

       CURLHEADER_SEPARATE - makes _HTTPHEADER&section=3">CURLOPT_HTTPHEADER(3) headers only get sent
       to a server and not to a proxy. Proxy headers must be set with
       _PROXYHEADER&section=3">CURLOPT_PROXYHEADER(3) 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 _PROXYHEADER&section=3">CURLOPT_PROXYHEADER(3)
       headers only to the proxy and then _HTTPHEADER&section=3">CURLOPT_HTTPHEADER(3) headers only
       to the server.

DEFAULT
       CURLHEADER_SEPARATE (changed in 7.42.1, used CURLHEADER_UNIFIED before
       then)

PROTOCOLS
       HTTP

EXAMPLE
       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);
       }

AVAILABILITY
       Added in 7.37.0

RETURN VALUE
       Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION
       if not.

SEE ALSO
       CURLOPT_HTTPHEADER(3), CURLOPT_PROXYHEADER(3),

libcurl 7.77.0                 November 4, 2020           CURLOPT_HEADEROPT(3)