This function is used to send the signal given by signal to the process whose ID is given by pid (but see below for more information). The process as which PHP is running will need adequate permissions to signal the intended recipient process.
If pid is positive, then signal will be sent to that process.
If pid is 0, then signal will be sent to every process in the current process's process group.
If pid is negative and not -1, then signal will be sent to every process in the process group identified by pid .
If pid is -1, then signal will be sent to every process save the first (counting from higher process numbers to lower).
Finally, if signal is equal to 0, then error checking is performed as usual but no signal is actually sent.
Note that as of PHP 4.0.6, named constants are not provided for signals; you will need to find out what the appropriate values for signals are on your system.
PHP Functions Essential Reference. Copyright © 2002 by New Riders Publishing (Authors: Zak Greant, Graeme Merrall, Torben Wilson, Brett Michlitsch). This material may be distributed only subject to the terms and conditions set forth in the Open Publication License, v1.0 or later (the latest version is presently available at http://www.opencontent.org/openpub/). The authors of this book have elected not to choose any options under the OPL. This online book was obtained from http://www.fooassociates.com/phpfer/ and is designed to provide information about the PHP programming language, focusing on PHP version 4.0.4 for the most part. The information is provided on an as-is basis, and no warranty or fitness is implied. All persons and entities shall have neither liability nor responsibility to any person or entity with respect to any loss or damage arising from the information contained in this book.