PROCESSES-AND-SIGNALS

Overview

This program demonstrates the creation and management of child processes in a Unix/Linux environment using the fork(), wait(), and signal() system calls. It creates a predefined number of child processes, manages their execution, and handles their termination appropriately. The program is designed to be compiled in two versions: one without signal handling and one with signal handling, directed by the WITH_SIGNALS preprocessor symbol.

Features

• Process Creation: Creates a specified number of child processes using fork().
• Delayed Execution: Introduces a one-second delay between consecutive fork() calls.
• Process Monitoring: Monitors and waits for all child processes to terminate.
• Signal Handling (Optional): Incorporates signal handling to demonstrate graceful interruption and process termination.

Compilation

The program can be compiled in two modes: with and without signal handling support. Use the following commands to compile the program accordingly:

• Without Signal Handling:

  gcc -o child_process_manager child_process_manager.c
  

• With Signal Handling:

  gcc -DWITH_SIGNALS -o child_process_manager child_process_manager.c
  

Running the Program

After compilation, you can run the program by executing:

./child_process_manager

Program Behavior

• Without Signal Handling: The program will create child processes, each printing its PID and its parent's PID, then sleep for 10 seconds before indicating its execution completion.
• With Signal Handling: In addition to the basic behavior, the program will handle signals differently. It will ignore most signals but restore the default handler for SIGCHLD. A custom handler for SIGINT (keyboard interrupt) will set a flag to notify the occurrence of an interrupt, affecting the creation of subsequent child processes.

Additional Notes

• The program utilizes standard Unix/Linux system calls such as fork(), wait(), signal(), and kill() to manage processes.
• It is designed to demonstrate basic process management and signal handling in a C program under a Unix/Linux environment.
• Ensure to check manual pages for system calls used (man 2 fork, man 2 wait, etc.) for a deeper understanding of their behavior.