curl / libcurl / API / curl_easy_setopt / CURLOPT_POSTFIELDSIZE

CURLOPT_POSTFIELDSIZE explained

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

Set the size of the data buffer to POST to prevent libcurl from doing a strlen() to figure out the data size. When this option 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 (if used) to signal the end of data.

You must make sure that the set size is not larger than the provided buffer.

If you post more than 2GB, use CURLOPT_POSTFIELDSIZE_LARGE.

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 returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors.