test.c

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

char* global_strs = NULL;


void do_free(void) {
    if (global_strs != NULL) {
        free(global_strs);
        puts("freed.");
    } else {
        puts("global_strs is already freed.");
    }
}

int main(int argc, char const* argv[]) {
    global_strs = malloc(1000 * sizeof(char));
    memset(global_strs, 0x1b, 1000 * sizeof(char));

    puts("malloced");

    do_free();

    return 0;
}