Section: curl_easy_setopt options (3)
Updated: March 23, 2020
CURLOPT_WRITEDATA - custom pointer passed to the write callback
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_WRITEDATA, void *pointer);
A data pointer
to pass to the write callback. If you use the
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
a 'FILE *' (cast to 'void *') as libcurl will pass this to
when writing data.
The internal CURLOPT_WRITEFUNCTION(3) 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 MUST use a
CURLOPT_WRITEFUNCTION(3) if you set this option or you will experience
By default, this is a FILE * to stdout.
Used for all protocols.
A common technique is to use the write callback to store the incoming data
into a dynamically growing allocated buffer, and then this
is used to point to a struct or the buffer to store
data in. Like in the getinmemory example:
Available in all libcurl versions. This option was formerly known as
, the name CURLOPT_WRITEDATA(3)
was introduced in
This will return CURLE_OK.