CURLOPT_POSTFIELDSIZE(3)    Library Functions Manual	CURLOPT_POSTFIELDSIZE(3)

NAME
     CURLOPT_POSTFIELDSIZE - size of POST data pointed to

SYNOPSIS
     #include <curl/curl.h>

     CURLcode curl_easy_setopt(CURL *handle, CURLOPT_POSTFIELDSIZE, long size);

DESCRIPTION
     If	 you  want to post static data to the server without having libcurl do a
     strlen() to measure the data size, this option must be used. When this  op-
     tion  is  used you can post fully binary data, which otherwise is likely to
     fail. If this size is set to -1, libcurl uses strlen() to get the	size  or
     relies on the CURLOPT_READFUNCTION(3) (if used) to signal the end of data.

     If you post more than 2GB, use CURLOPT_POSTFIELDSIZE_LARGE(3).

DEFAULT
     -1

PROTOCOLS
     This functionality affects http, mqtt and rtsp

EXAMPLE
     #include <string.h> /* for strlen */

     int main(void)
     {
       CURL *curl = curl_easy_init();
       if(curl) {
	 CURLcode result;
	 static const char *data = "data to send";

	 curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

	 /* size of the POST data */
	 curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, (long)strlen(data));

	 curl_easy_setopt(curl, CURLOPT_POSTFIELDS, data);

	 result = curl_easy_perform(curl);
	 curl_easy_cleanup(curl);
       }
     }

AVAILABILITY
     Added in curl 7.2

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_POSTFIELDS(3), CURLOPT_POSTFIELDSIZE_LARGE(3)

libcurl				   2026-09-14		CURLOPT_POSTFIELDSIZE(3)