curl / libcurl / API / curl_easy_setopt / CURLOPT_READDATA

CURLOPT_READDATA explained

Name

CURLOPT_READDATA - pointer passed to the read callback

Synopsis

#include <curl/curl.h>
 
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_READDATA, void *pointer);

Description

Data pointer to pass to the file read function. If you use the CURLOPT_READFUNCTION option, this is the pointer you get as input in the fourth argument to the callback.

If you do not specify a read callback but instead rely on the default internal read function, this data must be a valid readable FILE * (cast to 'void *').

If you are using libcurl as a DLL on Windows, you must use the CURLOPT_READFUNCTION callback if you set this option, otherwise you might experience crashes.

Default

stdin

Protocols

This functionality affects all supported protocols

Example

struct MyData {
  void *custom;
};
 
int main(void)
{
  CURL *curl = curl_easy_init();
  struct MyData this;
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
 
    /* pass pointer that gets passed in to the
       CURLOPT_READFUNCTION callback */
    curl_easy_setopt(curl, CURLOPT_READDATA, &this);
 
    curl_easy_perform(curl);
  }
}

History

This option was once known by the older name CURLOPT_INFILE, the name CURLOPT_READDATA was introduced in 7.9.7.

Availability

Added in curl 7.9.7

Return value

This returns CURLE_OK.