#include <sys/mman.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>

struct list {
  char data[500];
};

int main(int argc, char *argv[argc+1]) {
  size_t len = 10 << 20;
  int fd = open(argv[1], O_CREAT | O_RDWR, S_IRUSR | S_IWUSR);
  if (fd == -1) {
    perror("open");
    return EXIT_FAILURE;
  }

  if (ftruncate(fd, len) == -1) {
    perror("truncate");
    return EXIT_FAILURE;
  }

  struct list *items = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
  if (items == MAP_FAILED) {
    perror("mmap");
    return EXIT_FAILURE;
  }

  for (int i = 0; i < 100; i++) {
    sprintf(items[i].data, "i am item # %d",  i);
  }

  msync(items, len, MS_SYNC);
  munmap(items, len);
  return EXIT_SUCCESS;
}