No cache version.
Caching disabled. Default setting for this page:enabled (code LNG204)
If the display is too slow, you can disable the user mode to view the cached version.
dio_fcntl
(PHP 4 >= 4.2.0, PHP 5 < 5.1.0)
dio_fcntl — Performs a c library fcntl on fd
Description
The dio_fcntl() function performs the
operation specified by cmd
on the file
descriptor fd
. Some commands require
additional arguments args
to be supplied.
Parameters
-
fd
-
The file descriptor returned by dio_open().
-
cmd
-
Can be one of the following operations:
-
F_SETLK
- Lock is set or cleared. If the lock is held by someone else dio_fcntl() returns -1. -
F_SETLKW
- likeF_SETLK
, but in case the lock is held by someone else, dio_fcntl() waits until the lock is released. -
F_GETLK
- dio_fcntl() returns an associative array (as described below) if someone else prevents lock. If there is no obstruction key "type" will set toF_UNLCK
. -
F_DUPFD
- finds the lowest numbered available file descriptor greater than or equal toargs
and returns them. -
F_SETFL
- Sets the file descriptors flags to the value specified byargs
, which can beO_APPEND
,O_NONBLOCK
orO_ASYNC
. To useO_ASYNC
you will need to use the PCNTL extension.
-
-
args
-
args
is an associative array, whencmd
isF_SETLK
orF_SETLLW
, with the following keys:-
start - offset where lock begins
-
length - size of locked area. zero means to end of file
-
whence - Where l_start is relative to: can be
SEEK_SET
,SEEK_END
andSEEK_CUR
-
type - type of lock: can be
F_RDLCK
(read lock),F_WRLCK
(write lock) orF_UNLCK
(unlock)
-
Examples
Example #1 Setting and clearing a lock
<?php
$fd = dio_open('/dev/ttyS0', O_RDWR);
if (dio_fcntl($fd, F_SETLK, Array("type"=>F_WRLCK)) == -1) {
// the file descriptor appears locked
echo "The lock can not be cleared. It is held by someone else.";
} else {
echo "Lock successfully set/cleared";
}
dio_close($fd);
?>
English translation
You have asked to visit this site in English. For now, only the interface is translated, but not all the content yet.If you want to help me in translations, your contribution is welcome. All you need to do is register on the site, and send me a message asking me to add you to the group of translators, which will give you the opportunity to translate the pages you want. A link at the bottom of each translated page indicates that you are the translator, and has a link to your profile.
Thank you in advance.
Document created the 30/01/2003, last modified the 26/10/2018
Source of the printed document:https://www.gaudry.be/en/php-rf-dio-fcntl.html
The infobrol is a personal site whose content is my sole responsibility. The text is available under CreativeCommons license (BY-NC-SA). More info on the terms of use and the author.
References
These references and links indicate documents consulted during the writing of this page, or which may provide additional information, but the authors of these sources can not be held responsible for the content of this page.
The author This site is solely responsible for the way in which the various concepts, and the freedoms that are taken with the reference works, are presented here. Remember that you must cross multiple source information to reduce the risk of errors.