CURLINFO_HEADER_SIZE(3)    Library Functions Manual    CURLINFO_HEADER_SIZE(3)

NAME
       CURLINFO_HEADER_SIZE - size of response headers

SYNOPSIS
       #include <curl/curl.h>

       CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_HEADER_SIZE, long *sizep);

DESCRIPTION
       Pass a pointer to a long to receive the total size of all the headers
       received, represented in HTTP/1-style header format. Measured in number
       of bytes.

       The total includes the size of any received headers suppressed by
       CURLOPT_SUPPRESS_CONNECT_HEADERS(3).

       The number of bytes transferred over the wire (or to the TLS backend)
       is different when using HTTP/2 or greater.

PROTOCOLS
       This functionality affects all supported protocols

EXAMPLE
       int main(void)
       {
         CURL *curl = curl_easy_init();
         if(curl) {
           CURLcode result;
           curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
           result = curl_easy_perform(curl);
           if(result == CURLE_OK) {
             long size;
             result = curl_easy_getinfo(curl, CURLINFO_HEADER_SIZE, &size);
             if(result == CURLE_OK)
               printf("Header size: %ld bytes\n", size);
           }
           curl_easy_cleanup(curl);
         }
       }

AVAILABILITY
       Added in curl 7.4.1

RETURN VALUE
       curl_easy_getinfo(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
       CURLINFO_REQUEST_SIZE(3), CURLINFO_SIZE_DOWNLOAD(3),
       curl_easy_getinfo(3), curl_easy_setopt(3)

libcurl                           2026-09-02           CURLINFO_HEADER_SIZE(3)