#define _GNU_SOURCE
#include <sys/mman.h>
#include <unistd.h>
#include <stdio.h>
int main() {
size_t size = 4096 * 2;
int fd = memfd_create("example", 0);
if (fd == -1)
return 0;
ftruncate(fd, size);
char *orig = (char *)mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
char *copy = (char *)mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
orig[0] += 100;
copy[0] += 10;
orig[0] += 1;
orig[4095] = 1;
orig[4096] = 1;
printf("%p, %p, diff: %zi\n", orig, copy, orig - copy);
printf("index orig copy\n");
printf("[0] %i %i\n", orig[0], copy[0]);
printf("[4095] %i %i\n", orig[4095], copy[4095]);
printf("[4096] %i %i\n", orig[4096], copy[4096]);
munmap(copy, size);
munmap(orig, size);
return 0;
}
