CURLOPT_WRITEDATA.md 1.6 KB
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 ---
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
By default, this is a FILE * to stdout.
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
AVAILABILITY
Available in all libcurl versions. This option was formerly known as CURLOPT_FILE, the name CURLOPT_WRITEDATA(3) was added in 7.9.7.
RETURN VALUE
This returns CURLE_OK.