.\" ************************************************************************** .\" * _ _ ____ _ .\" * Project ___| | | | _ \| | .\" * / __| | | | |_) | | .\" * | (__| |_| | _ <| |___ .\" * \___|\___/|_| \_\_____| .\" * .\" * Copyright (C) 1998 - 2015, 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.haxx.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 "16 Jun 2014" "libcurl 7.37.0" "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.haxx.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), "