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CURLOPT_HEADER(3)                   libcurl                  CURLOPT_HEADER(3)

NAME
       CURLOPT_HEADER - pass headers to the data stream

SYNOPSIS
       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HEADER, long onoff);

DESCRIPTION
       Pass the long value onoff set to 1 to ask libcurl to include the
       headers in the write callback (CURLOPT_WRITEFUNCTION(3)). 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 CURLOPT_WRITEFUNCTION(3) callback is limited to only ever
       get a maximum of CURL_MAX_WRITE_SIZE bytes passed to it (16KB), while a
       header can be longer and the CURLOPT_HEADERFUNCTION(3) supports getting
       called with headers up to CURL_MAX_HTTP_HEADER bytes big (100KB).

       It is often better to use CURLOPT_HEADERFUNCTION(3) to get the header
       data separately.

       While named confusingly similar, CURLOPT_HTTPHEADER(3) is used to set
       custom HTTP headers!

DEFAULT
       0

PROTOCOLS
       Most

EXAMPLE
       CURL *curl = curl_easy_init();
       if(curl) {
         curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

         curl_easy_setopt(curl, CURLOPT_HEADER, 1L);

         curl_easy_perform(curl);
       }

AVAILABILITY
       Provided in all libcurl versions.

RETURN VALUE
       Returns CURLE_OK.

SEE ALSO
       CURLOPT_HEADERFUNCTION(3),  CURLOPT_HTTPHEADER(3),

ibcurl 8.1.2                    April 26, 2023               CURLOPT_HEADER(3)