from small one page howto to huge articles all in one place
 

search text in:





Poll
Which linux distribution do you use?







poll results

Last additions:
using iotop to find disk usage hogs

using iotop to find disk usage hogs

words:

887

views:

99201

userrating:

average rating: 1.7 (84 votes) (1=very good 6=terrible)


May 25th. 2007:
Words

486

Views

214374

why adblockers are bad


Workaround and fixes for the current Core Dump Handling vulnerability affected kernels

Workaround and fixes for the current Core Dump Handling vulnerability affected kernels

words:

161

views:

95426

userrating:

average rating: 1.3 (28 votes) (1=very good 6=terrible)


April, 26th. 2006:

Druckversion
You are here: manpages





CURLOPT_WRITEFUNCTION

Section: curl_easy_setopt options (3)
Updated: 16 Jun 2014
Index Return to Main Contents
 

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: http://curl.haxx.se/libcurl/c/getinmemory.html  

SEE ALSO

CURLOPT_WRITEDATA(3), CURLOPT_READFUNCTION(3),


 

Index

NAME
SYNOPSIS
DESCRIPTION
DEFAULT
PROTOCOLS
AVAILABILITY
RETURN VALUE
EXAMPLE
SEE ALSO


Please read "Why adblockers are bad".



Other free services
toURL.org
Shorten long
URLs to short
links like
http://tourl.org/2
tourl.org
.
Reverse DNS lookup
Find out which hostname(s)
resolve to a
given IP or other hostnames for the server
www.reversednslookup.org
rdf newsfeed | rss newsfeed | Atom newsfeed
- Powered by LeopardCMS - Running on Gentoo -
Copyright 2004-2017 Sascha Nitsch Unternehmensberatung UG(haftungsbeschränkt)
Valid XHTML1.1 : Valid CSS : buttonmaker
- Level Triple-A Conformance to Web Content Accessibility Guidelines 1.0 -
- Copyright and legal notices -
Time to create this page: 3.6 ms