Practical C Programming

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If there is more than one function that is registered via the atexit function, then these functions will be executed in LIFO order. To understand this, let's modify the preceding atexistprog1.c program to register two functions via the atexit function. We will save the modified program as atexistprog2.c as follows (atexistprog2.c):

#include <stdio.h> #include <stdlib.h> char *str; void freeup1() {    free(str);     printf( "Allocated memory is freed  \n"); } void freeup2(){     printf( "The size of dynamic memory can be increased and decreased  \n"); } int main() {    int retvalue;     retvalue = atexit(freeup1);     if (retvalue != 0) {         printf("Registration of function freeup1() for atexit ()           function failed\n");         exit(1);     } retvalue = atexit(freeup2); ...