CURLOPT_HEADEROPT(3)

NAME
CURLOPT_HEADEROPT - send HTTP headers to both proxy and host or separately

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 CURLOPT_HTTPHEADER(3) are used in requests both to servers and proxies. With this option enabled, CURLOPT_PROXYHEADER(3) does not have any effect. CURLHEADER_SEPARATE - makes CURLOPT_HTTPHEADER(3) headers only get sent to a server and not to a proxy. Proxy headers must be set with CURLOPT_PROXYHEADER(3) to get used. Note that if a non-CONNECT request is sent to a proxy, libcurl sends both server headers and proxy headers. When doing CONNECT, libcurl sends CURLOPT_PROXYHEADER(3) headers only to the proxy and then CURLOPT_HTTPHEADER(3) headers only to the server.

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

PROTOCOLS
This functionality affects http only

EXAMPLE
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    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);
    result = curl_easy_perform(curl);
    curl_slist_free_all(list);
    curl_easy_cleanup(curl);
  }
}

HISTORY
CURLHEADER_* macros became long types in 8.16.0, prior to this version a long cast was necessary when passed to curl_easy_setopt(3).

AVAILABILITY
Added in curl 7.37.0

RETURN VALUE
curl_easy_setopt(3) returns a CURLcode indicating success or error. CURLE_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors(3).

SEE ALSO
CURLOPT_HTTPHEADER(3), CURLOPT_PROXYHEADER(3)