a86c63ca
 Hu Chunming
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.\" **************************************************************************
.\" * _ _ ____ _
.\" * Project ___| | | | _ \| |
.\" * / __| | | | |_) | |
.\" * | (__| |_| | _ <| |___
.\" * \___|\___/|_| \_\_____|
.\" *
.\" * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
.\" *
.\" * This software is licensed as described in the file COPYING, which
.\" * you should have received as part of this distribution. The terms
.\" * are also available at https://curl.se/docs/copyright.html.
.\" *
.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
.\" * copies of the Software, and permit persons to whom the Software is
.\" * furnished to do so, under the terms of the COPYING file.
.\" *
.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
.\" * KIND, either express or implied.
.\" *
.\" **************************************************************************
.\"
.TH CURLOPT_WRITEDATA 3 "November 04, 2020" "libcurl 7.77.0" "curl_easy_setopt options"
.SH NAME
CURLOPT_WRITEDATA \- custom pointer passed to the write callback
.SH SYNOPSIS
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_WRITEDATA, void *pointer);
.SH DESCRIPTION
A data \fIpointer\fP to pass to the write callback. If you use the
\fICURLOPT_WRITEFUNCTION(3)\fP option, this is the pointer you'll get in that
callback's 4th argument. If you don't use a write callback, you must make
\fIpointer\fP a 'FILE *' (cast to 'void *') as libcurl will pass this to
\fIfwrite(3)\fP when writing data.
The internal \fICURLOPT_WRITEFUNCTION(3)\fP will write the data to the FILE *
given with this option, or to stdout if this option hasn't been set.
If you're using libcurl as a win32 DLL, you \fBMUST\fP use a
\fICURLOPT_WRITEFUNCTION(3)\fP if you set this option or you will experience
crashes.
.SH DEFAULT
By default, this is a FILE * to stdout.
.SH PROTOCOLS
Used for all protocols.
.SH EXAMPLE
A common technique is to use the write callback to store the incoming data
into a dynamically growing allocated buffer, and then this
\fICURLOPT_WRITEDATA(3)\fP 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
.SH AVAILABILITY
Available in all libcurl versions. This option was formerly known as
\fICURLOPT_FILE\fP, the name \fICURLOPT_WRITEDATA(3)\fP was introduced in
7.9.7.
.SH RETURN VALUE
This will return CURLE_OK.
.SH "SEE ALSO"
.BR CURLOPT_WRITEFUNCTION "(3), " CURLOPT_READDATA "(3), "
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