libcurl手册-CURLOPT_WRITEDATA

CURLOPT_WRITEDATA(3) curl_easy_setopt options

CURLOPT_WRITEDATA(3)

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 will 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 will pass this to fwrite(3) 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 has not been set.

   If you are using libcurl as a win32 DLL, you MUST use a CURLOPT_WRITEFUNCTION(3) if you set this option or you
   will experience crashes.

要注意Win32 DLL下，如果设置了这个选项，就必须设置CURLOPT_WRITEFUNCTION，否则程序会崩溃。

DEFAULT

   By default, this is a FILE * to stdout.

PROTOCOLS

   Used for all protocols.

EXAMPLE

   A  common  technique  is to use the write callback to store the incoming data into a dynamically growing allo‐
   cated 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_WRITE‐
   DATA(3) was introduced in 7.9.7.

RETURN VALUE

   This will return CURLE_OK.

SEE ALSO

   CURLOPT_WRITEFUNCTION(3), CURLOPT_READDATA(3),

libcurl 7.88.1 January 02, 2023 CURLOPT_WRITEDATA(3)