.\" ************************************************************************** .\" * _ _ ____ _ .\" * Project ___| | | | _ \| | .\" * / __| | | | |_) | | .\" * | (__| |_| | _ <| |___ .\" * \___|\___/|_| \_\_____| .\" * .\" * Copyright (C) 1998 - 2018, 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_HEADER 3 "16 Jun 2014" "libcurl 7.37.0" "curl_easy_setopt options" .SH NAME CURLOPT_HEADER \- pass headers to the data stream .SH SYNOPSIS #include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HEADER, long onoff); .SH DESCRIPTION Pass the long value \fIonoff\fP set to 1 to ask libcurl to include the headers in the write callback (\fICURLOPT_WRITEFUNCTION(3)\fP). This option is relevant for protocols that actually have headers or other meta-data (like HTTP and FTP). When asking to get the headers passed to the same callback as the body, it is not possible to accurately separate them again without detailed knowledge about the protocol in use. Further: the \fCURLOPT_WRITEFUNCTION(3)\fP callback is limited to only ever get a maximum of \fICURL_MAX_WRITE_SIZE\fP bytes passed to it (16KB), while a header can be longer and the \fICURLOPT_HEADERFUNCTION(3)\fP supports getting called with headers up to \fICURL_MAX_HTTP_HEADER\fP bytes big (100KB). It is often better to use \fICURLOPT_HEADERFUNCTION(3)\fP to get the header data separately. While named confusingly similar, \fICURLOPT_HTTPHEADER(3)\fP is used to set custom HTTP headers! .SH DEFAULT 0 .SH PROTOCOLS Most .SH EXAMPLE .nf CURL *curl = curl_easy_init(); if(curl) { curl_easy_setopt(curl, CURLOPT_URL, "http://example.com"); curl_easy_setopt(curl, CURLOPT_HEADER, 1L); curl_easy_perform(curl); } .fi .SH RETURN VALUE Returns CURLE_OK. .SH "SEE ALSO" .BR CURLOPT_HEADERFUNCTION "(3), " .BR CURLOPT_HTTPHEADER "(3), "