curl/docs/libcurl/opts/CURLOPT_WRITEDATA.3

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.TH CURLOPT_WRITEDATA 3 "16 Jun 2014" "libcurl 7.37.0" "curl_easy_setopt options"
.SH NAME
CURLOPT_WRITEDATA \- pointer passed to the write callback
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_WRITEDATA, void *pointer);
.fi
.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 will get in that
callback's 4th argument. If you do not 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 has not been set.

If you are 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), "