CURLOPT_COPYPOSTFIELDS - Man Page

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_COPYPOSTFIELDS, char *data);

Pass a char pointer as parameter, which should be the full data to post in a HTTP POST operation. It behaves as the CURLOPT_POSTFIELDS(3) option, but the original data is instead copied by the library, allowing the application to overwrite the original data after setting this option.

Because data is copied, care must be taken when using this option in conjunction with CURLOPT_POSTFIELDSIZE(3) or CURLOPT_POSTFIELDSIZE_LARGE(3). If the size has not been set prior to CURLOPT_COPYPOSTFIELDS(3), the data is assumed to be a null-terminated string; else the stored size informs the library about the byte count to copy. In any case, the size must not be changed after CURLOPT_COPYPOSTFIELDS(3), unless another CURLOPT_POSTFIELDS(3) or CURLOPT_COPYPOSTFIELDS(3) option is set.

The application does not have to keep the string around after setting this option.

Using this option multiple times makes the last set string override the previous ones. Set it to NULL to disable its use again.

NULL

This functionality affects http only

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    char local_buffer[1024]="data to send";
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

    /* size of the data to copy from the buffer and send in the request */
    curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, 12L);

    /* send data from the local stack */
    curl_easy_setopt(curl, CURLOPT_COPYPOSTFIELDS, local_buffer);

    curl_easy_perform(curl);
  }
}

Added in curl 7.17.1

Returns CURLE_OK if the option is supported, CURLE_UNKNOWN_OPTION if not, or CURLE_OUT_OF_MEMORY if there was insufficient heap space.

CURLOPT_MIMEPOST(3), CURLOPT_POSTFIELDS(3), CURLOPT_POSTFIELDSIZE(3), CURLOPT_UPLOAD(3)

curl_easy_setopt(3), CURLOPT_POST(3), CURLOPT_POSTFIELDS(3), CURLOPT_POSTFIELDSIZE_LARGE(3), libcurl-symbols(3).