#include <stdio.h>
#include <sys/mman.h>
#include <string.h>

int main(void)
{
    char *data1 = "HELLO";
    char data2[] = "Hello Master";

    if (mprotect(data1, strlen(data1) + 1, PROT_WRITE) == 0)
    {
        data1[0] = (char)'F';
        printf("Data1 is writable: %s, %p, %ld chars\n", data1, data1, strlen(data1));
        printf("Data2 is writable: %s, %p, %ld chars\n", data2, data2, strlen(data2));
    }
    else
    {
        data2[0] = (char)'F';
        printf("Data1 is not writable: %s, %p, %ld chars\n", data1, data1, strlen(data1));
        printf("Data1 is not writable: %s, %p, %ld chars\n", data2, data2, strlen(data2));
    }
}