This is proc/mem_segments.c (Listing 6-1, page 117), an example from the book, The Linux Programming Interface.

The source code file is copyright 2022, Michael Kerrisk, and is licensed under the GNU General Public License, version 3.

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/* mem_segments.c

   A program that does nothing in particular, but the comments indicate
   which memory segments each type of variable is allocated in.
#define _BSD_SOURCE
#include <stdio.h>
#include <stdlib.h>

char globBuf[65536];            /* Uninitialized data segment */
int primes[] = { 2, 3, 5, 7 };  /* Initialized data segment */
static int
square(int x)                   /* Allocated in frame for square() */
    int result;                 /* Allocated in frame for square() */

    result = x * x;
    return result;              /* Return value passed via register */
static void
doCalc(int val)                 /* Allocated in frame for doCalc() */
    printf("The square of %d is %d\n", val, square(val));

    if (val < 1000) {
        int t;                  /* Allocated in frame for doCalc() */

        t = val * val * val;
        printf("The cube of %d is %d\n", val, t);
main(int argc, char *argv[])    /* Allocated in frame for main() */
    static int key = 9973;      /* Initialized data segment */
    static char mbuf[10240000]; /* Uninitialized data segment */
    char *p;                    /* Allocated in frame for main() */

    p = malloc(1024);           /* Points to memory in heap segment */




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