curl/docs/libcurl/opts/CURLOPT_WRITEDATA.md

---

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

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

NAME

CURLOPT_WRITEDATA - pointer passed to the write callback

SYNOPSIS

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_WRITEDATA, void *pointer);

DESCRIPTION

A data pointer to pass to the write callback. If you use the CURLOPT_WRITEFUNCTION(3) option, this is the pointer you get in that callback's fourth and last argument. If you do not use a write callback, you must make pointer a 'FILE *' (cast to 'void *') as libcurl passes this to fwrite(3) when writing data.

The internal CURLOPT_WRITEFUNCTION(3) writes the data to the FILE * given with this option, or to stdout if this option has not been set.

If you are using libcurl as a Windows DLL, you MUST use a CURLOPT_WRITEFUNCTION(3) if you set this option or you might experience crashes.

DEFAULT

stdout

%PROTOCOLS%

EXAMPLE

A common technique is to use the write callback to store the incoming data into a dynamically growing allocated buffer, and then this CURLOPT_WRITEDATA(3) is used to point to a struct or the buffer to store data in. Like in the getinmemory example: https://curl.se/libcurl/c/getinmemory.html

HISTORY

This option was formerly known as CURLOPT_FILE, the name CURLOPT_WRITEDATA(3) was added in 7.9.7.

%AVAILABILITY%

RETURN VALUE

This returns CURLE_OK.