CURLINFO_HEADER_SIZE(3)

CURLINFO_HEADER_SIZE3

Size of response headers

Usage

#include <curl/curl.h>
CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_HEADER_SIZE, long *sizep);

Overview

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

Examples

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);
  }
}

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).

Releases

6 releases since Debian 9 (Stretch); the text changed 5 times.

  1. 9
  2. 10
  3. 11
  4. 12
  5. 13
  6. Arch

Availability

Added in curl 7.4.1

From curl 8.23.0-1 in Arch Linux 2026-11-01. Parsed by carta from the page's man source.