Process Control support in PHP implements the Unix style of process creation, program execution, signal handling and process termination. Process Control should not be enabled within a webserver environment and unexpected results may happen if any Process Control functions are used within a webserver environment.
This documentation is intended to explain the general usage of each of the Process Control functions. For detailed information about Unix process control you are encouraged to consult your systems documentation including fork(2), waitpid(2) and signal(2) or a comprehensive reference such as Advanced Programming in the UNIX Environment by W. Richard Stevens (Addison-Wesley).
Note: This extension is not available on Windows platforms.
Process Control support in PHP is not enabled by default. You will need to use the --enable-pcntl configuration option when compiling PHP to enable Process Control support.
Note: Currently, this module will not function on non-Unix platforms (Windows).
The following list of signals are supported by the Process Control functions. Please see your systems signal(7) man page for details of the default behavior of these signals.
This example forks off a daemon process with a signal handler.
Example 1. Process Control Example
A look at the section about POSIX functions may be useful.