74 lines
3.1 KiB
Groff
74 lines
3.1 KiB
Groff
.\" **************************************************************************
|
|
.\" * _ _ ____ _
|
|
.\" * Project ___| | | | _ \| |
|
|
.\" * / __| | | | |_) | |
|
|
.\" * | (__| |_| | _ <| |___
|
|
.\" * \___|\___/|_| \_\_____|
|
|
.\" *
|
|
.\" * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
|
|
.\" *
|
|
.\" * This software is licensed as described in the file COPYING, which
|
|
.\" * you should have received as part of this distribution. The terms
|
|
.\" * are also available at http://curl.haxx.se/docs/copyright.html.
|
|
.\" *
|
|
.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
|
|
.\" * copies of the Software, and permit persons to whom the Software is
|
|
.\" * furnished to do so, under the terms of the COPYING file.
|
|
.\" *
|
|
.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
|
|
.\" * KIND, either express or implied.
|
|
.\" *
|
|
.\" **************************************************************************
|
|
.\"
|
|
.TH CURLOPT_SEEKFUNCTION 3 "16 Jun 2014" "libcurl 7.37.0" "curl_easy_setopt options"
|
|
.SH NAME
|
|
CURLOPT_SEEKFUNCTION \- user callback for seeking in input stream
|
|
.SH SYNOPSIS
|
|
.nf
|
|
#include <curl/curl.h>
|
|
|
|
/* These are the return codes for the seek callbacks */
|
|
#define CURL_SEEKFUNC_OK 0
|
|
#define CURL_SEEKFUNC_FAIL 1 /* fail the entire transfer */
|
|
#define CURL_SEEKFUNC_CANTSEEK 2 /* tell libcurl seeking can't be done, so
|
|
libcurl might try other means instead */
|
|
|
|
int seek_callback(void *userp, curl_off_t offset, int origin);
|
|
|
|
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SEEKFUNCTION, seek_callback);
|
|
.SH DESCRIPTION
|
|
Pass a pointer to your callback function, which should match the prototype
|
|
shown above.
|
|
|
|
This function gets called by libcurl to seek to a certain position in the
|
|
input stream and can be used to fast forward a file in a resumed upload
|
|
(instead of reading all uploaded bytes with the normal read
|
|
function/callback). It is also called to rewind a stream when doing a HTTP PUT
|
|
or POST with a multi-pass authentication method. The function shall work like
|
|
fseek(3) or lseek(3) and it gets SEEK_SET, SEEK_CUR or SEEK_END as argument
|
|
for \fIorigin\fP, although libcurl currently only passes SEEK_SET.
|
|
|
|
\fIuserp\fP is the pointer you set with \fICURLOPT_SEEKDATA(3)\fP.
|
|
|
|
The callback function must return \fICURL_SEEKFUNC_OK\fP on success,
|
|
\fICURL_SEEKFUNC_FAIL\fP to cause the upload operation to fail or
|
|
\fICURL_SEEKFUNC_CANTSEEK\fP to indicate that while the seek failed, libcurl
|
|
is free to work around the problem if possible. The latter can sometimes be
|
|
done by instead reading from the input or similar.
|
|
|
|
If you forward the input arguments directly to fseek(3) or lseek(3), note that
|
|
the data type for \fIoffset\fP is not the same as defined for curl_off_t on
|
|
many systems!
|
|
.SH DEFAULT
|
|
By default, this is NULL and unused.
|
|
.SH PROTOCOLS
|
|
HTTP, FTP, SFTP
|
|
.SH EXAMPLE
|
|
TODO
|
|
.SH AVAILABILITY
|
|
Added in 7.18.0
|
|
.SH RETURN VALUE
|
|
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
|
|
.SH "SEE ALSO"
|
|
.BR CURLOPT_SEEKDATA "(3), " CURLOPT_IOCTLFUNCTION "(3), "
|