curl/docs/libcurl/opts/CURLOPT_READDATA.md

---

c: Copyright (C) Daniel Stenberg, daniel@haxx.se, et al. SPDX-License-Identifier: curl Title: CURLOPT_READDATA Section: 3 Source: libcurl See-also:

• CURLOPT_HEADERDATA (3)
• CURLOPT_READFUNCTION (3)
• CURLOPT_WRITEDATA (3)
• CURLOPT_WRITEFUNCTION (3) Protocol:
• All Added-in: 7.9.7 ---

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(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.

DEFAULT

stdin

%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(3) was introduced in 7.9.7.

%AVAILABILITY%

RETURN VALUE

This returns CURLE_OK.