The PHP Function pcntl_sigwaitinfo

PHP Functions are a powerful tool for splitting and reusing your program logic. They are used to take input, process it, and return a value. There are thousands of built-in functions in PHP that can handle many common programming tasks. They may come from the standard PHP distribution or additional extensions compiled with PHP. You can also write your own functions for unique needs.

In this article, we will explore a very useful function called pcntl_sigwaitinfo. This function suspends execution of the calling script until one or more signals given in its set are delivered. The siginfo parameter is set to an array containing information about the signal. On success, pcntl_sigwaitinfo() returns a signal number.

This function can be useful in cases where you need to manage child processes. For example, you can use it to keep track of multiple child processes and terminate them if necessary to avoid zombies.

Another useful function is pcntl_fork(), which creates a new process to execute your code. This function is used to prevent your website from becoming unresponsive because of a file lock or other problems with the file system.

When creating a function, you must specify its type as either void or function. This is important because if the function’s type mismatches with its argument list, the PHP interpreter will throw a fatal error. In addition, you must use the question mark prefix with all functions that accept variables. This is because PHP is a loosely-typed language that performs some type juggling when it assigns a variable to a function.