CURLOPT_READDATA(3) Library Functions Manual CURLOPT_READDATA(3)

CURLOPT_READDATA - pointer passed to the read callback

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

Data pointer to pass to the file read function. If you use the CURLOPT_READFUNCTION(3) 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(3) callback if you set this option, otherwise you might experience crashes.

By default, this is a FILE * to stdin.

All

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);
  }
}

This option was once known by the older name CURLOPT_INFILE, the name CURLOPT_READDATA(3) was introduced in 7.9.7.

This returns CURLE_OK.

CURLOPT_HEADERDATA(3), CURLOPT_READFUNCTION(3), CURLOPT_WRITEDATA(3), CURLOPT_WRITEFUNCTION(3)

2024-05-22 libcurl