unixmemory.c

#define _GNU_SOURCE // needed for MAP_ANONYMOUS
#include <stdio.h>
#include <sys/mman.h>

int main(void)
{
    void *ptr = mmap(NULL, 24, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
    if (ptr == MAP_FAILED) {
        perror("mmap");
        return 1;
    }
    int status = mprotect(ptr, 24, PROT_READ);
    if (status != 0) {
        perror("mprotect");
        return 1;
    }
    status = munmap(ptr, 24);
    if (status != 0) {
        perror("munmap");
        return 1;
    }
    return 0;
}