C Exercises: Set a function that will be executed on termination of a program

Last update on March 18 2025 13:37:43 (UTC/GMT +8 hours)

15. Exit Function Registration

Write a C program to set a function that will be executed on termination of a program.

Sample Solution:

C Code:

#include<stdio.h>      // Include the standard input/output header file.
#include<stdlib.h>     // Include the standard library header file.

// Function to be executed when the program exits.
void newFunctionOne (void)
{
puts (" Here is the message returning from newFunctionOne.");
}

// Another function to be executed when the program exits.
void newFunctionTwo (void)
{
puts (" Here is the message returning from newFunctionTwo.");
}

int main ()          // Start of the main function.
{
atexit (newFunctionOne);   // Register 'newFunctionOne' to be executed at program exit.
atexit (newFunctionTwo);   // Register 'newFunctionTwo' to be executed at program exit.

puts ("\n This is the message from main function.");   // Print a message from the main function.

return 0;   // Return 0 to indicate successful execution of the program.
}   // End of the main function.

Sample Output:

 This is the message from main function.                                                                      
 Here is the message returning from newFunctionTwo.                                                           
 Here is the message returning from newFunctionOne

Flowchart:

For more Practice: Solve these Related Problems:

Write a C program to register an exit handler using atexit() that logs a message to a file upon termination.
Write a C program to register multiple functions with atexit() and observe the order in which they are executed.
Write a C program to register an exit function that cleans up dynamically allocated memory before the program ends.
Write a C program to demonstrate the use of atexit() by executing a cleanup routine when the program terminates normally.

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