curlopt_writedata(3) [mojave man page]

CURLOPT_WRITEDATA(3)					     curl_easy_setopt options					      CURLOPT_WRITEDATA(3)

NAME

       CURLOPT_WRITEDATA - custom 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'll get in that call-
       back's 4th argument. If you don't 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 hasn't been
       set.

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

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 allocated buffer, and then this  CUR-
       LOPT_WRITEDATA(3)   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

AVAILABILITY

       Available in all libcurl versions. This option was formerly known as CURLOPT_FILE, the name CURLOPT_WRITEDATA(3) was introduced in 7.9.7.

RETURN VALUE

       This will return CURLE_OK.

SEE ALSO

       CURLOPT_WRITEFUNCTION(3), CURLOPT_READDATA(3),

libcurl 7.54.0							 February 03, 2016					      CURLOPT_WRITEDATA(3)

CURLOPT_WRITEFUNCTION(3)				     curl_easy_setopt options					  CURLOPT_WRITEFUNCTION(3)

NAME

       CURLOPT_WRITEFUNCTION - set callback for writing received data

SYNOPSIS

       #include <curl/curl.h>

       size_t write_callback(char *ptr, size_t size, size_t nmemb, void *userdata);

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_WRITEFUNCTION, write_callback);

DESCRIPTION

       Pass a pointer to your callback function, which should match the prototype shown above.

       This  callback function gets called by libcurl as soon as there is data received that needs to be saved.  ptr points to the delivered data,
       and the size of that data is size multiplied with nmemb.

       The callback function will be passed as much data as possible in all invokes, but you must not make any assumptions. It may be one byte, it
       may  be	thousands.  The  maximum  amount  of  body  data  that	will be passed to the write callback is defined in the curl.h header file:
       CURL_MAX_WRITE_SIZE (the usual default is 16K). If CURLOPT_HEADER(3) is enabled, which makes header data get passed to the write  callback,
       you can get up to CURL_MAX_HTTP_HEADER bytes of header data passed into it. This usually means 100K.

       This function may be called with zero bytes data if the transferred file is empty.

       The data passed to this function will not be zero terminated!

       Set the userdata argument with the CURLOPT_WRITEDATA(3) option.

       Your  callback  should  return  the  number of bytes actually taken care of. If that amount differs from the amount passed to your callback
       function, it'll signal an error condition to the library. This will cause the transfer to get aborted and the libcurl  function	used  will
       return CURLE_WRITE_ERROR.

       If  your  callback  function returns CURL_WRITEFUNC_PAUSE it will cause this transfer to become paused.	See curl_easy_pause(3) for further
       details.

       Set this option to NULL to get the internal default function used instead of your callback. The internal default function  will	write  the
       data to the FILE * given with CURLOPT_WRITEDATA(3).

DEFAULT

       libcurl will use 'fwrite' as a callback by default.

PROTOCOLS

       For all protocols

AVAILABILITY

       Support for the CURL_WRITEFUNC_PAUSE return code was added in version 7.18.0.

RETURN VALUE

       This will return CURLE_OK.

EXAMPLE

       A  common technique is to use this callback to store the incoming data into a dynamically growing allocated buffer. Like in the getinmemory
       example: https://curl.haxx.se/libcurl/c/getinmemory.html

SEE ALSO

       CURLOPT_WRITEDATA(3), CURLOPT_READFUNCTION(3),

libcurl 7.54.0							 February 03, 2016					  CURLOPT_WRITEFUNCTION(3)