Program to map a persistent memory file

map.c

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

#define MAP_SYNC            0x80000
#define MAP_SHARED_VALIDATE 0x03
#define FILE_LEN            1024 * 1024 // 1MB

int main() {
    char *file = "/mnt/ext4-pmem0/file";
    int fd = open(file, O_RDWR | O_CREAT);
    if (fd < 0) {
        printf("File open failed - %d\n", errno);
        exit(1);
    }

    if (ftruncate(fd, FILE_LEN) != 0) {
        printf("File truncate failed - %d\n", errno);
        exit(1);
    }

    if (posix_fallocate(fd, 0, FILE_LEN) != 0) {
        printf("posix_fallocate failed - %d\n", errno);
        exit(1);
    }

    void *addr = mmap(NULL, FILE_LEN, PROT_READ|PROT_WRITE,
                      MAP_SHARED | MAP_SHARED_VALIDATE | MAP_SYNC,
                      fd, 0);

    if (addr == MAP_FAILED) {
        printf("Persistent memory map failed - %d\n", errno);
        exit(1);
    }

    printf("Persistent memory file successfully mapped at address %p\n", addr);

    return 0;
}