shm_open doesn't work about toolbox HOT 4 CLOSED

/* gcc shm.c -lrt */

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

int
main (void)
{
  int fd;

  fd = shm_open ("/foo", O_CREAT | O_RDWR, 0664);
  if (fd == -1)
    {
      fprintf (stderr, "shm_open failed: %s\n", strerror (errno));
      return 1;
    }

  close (fd);
  return 0;
}

🔹[rishi@toolbox ~]$ echo hello world >/dev/shm/bar
🔹[rishi@toolbox ~]$ ls -l /dev/shm
total 4
-rw-rw-r--. 1 rishi rishi 12 Nov  6 18:48 bar
🔹[rishi@toolbox ~]$ cat /dev/shm/bar
hello world

🔹[rishi@toolbox ~]$ df -h /dev
Filesystem      Size  Used Avail Use% Mounted on
tmpfs            64M     0   64M   0% /dev
🔹[rishi@toolbox ~]$ df -h /dev/shm
Filesystem      Size  Used Avail Use% Mounted on
/dev/nvme0n1p5  415G   28G  366G   7% /dev/shm