PHP pcntl fork

Info to remember for pcntl_fork in PHP

When using the `pcntl_fork()` function in PHP, the mode in which the fork operation is performed can be either blocking or non-blocking. Here's the difference between the two:

1. Blocking Mode:

  In blocking mode, the parent process waits for the child process to complete before continuing its execution. When `pcntl_fork()` is called in blocking mode, the parent process will pause until the child process finishes its execution and exits. The parent process will receive the exit status of the child process and can perform any necessary cleanup or further actions based on that status.

2. Non-blocking Mode:

  In non-blocking mode, the parent process continues its execution immediately after forking the child process, without waiting for the child process to complete. When `pcntl_fork()` is called in non-blocking mode, the parent process will receive the process ID (PID) of the child process and can continue with its execution. The child process will execute concurrently with the parent process. In this mode, it's the responsibility of the parent process to handle the coordination and synchronization with the child process, if needed, using mechanisms such as signals, pipes, or shared memory.

Choosing between blocking and non-blocking mode depends on the specific requirements of your application:

- Blocking mode is useful when you want to ensure that the parent process has the results of the child process before proceeding further. This mode allows for a simpler control flow, as the parent process waits for the child process to finish.

- Non-blocking mode is useful when you want the parent process to continue its execution immediately and potentially perform other tasks concurrently with the child process. This mode allows for parallel execution and can be beneficial when the child process performs independent or long-running tasks.

It's important to note that `pcntl_fork()` is a low-level function that provides process forking capabilities. Handling child processes and managing synchronization between them requires additional programming using mechanisms such as signals, shared memory, or inter-process communication (IPC) techniques like pipes or message queues.