fchown fails after shm_open on MacOS X C

Question

I want to open a shared memory file on MacOSX Monterey and then change the mode for read only.

I get the error message "invalid argument". is this the expected behavior on shared mem files or I'm missing something?

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

int main() {
   int fd = shm_open("some_name", O_CREAT | O_EXCL | O_RDWR, S_IWUSR | S_IRUSR | S_IRGRP);  // 0640
   if (fd == -1) {
       perror("shm_open");
       exit(EXIT_FAILURE);
   }

    if (fchmod(fd, S_IRUSR | S_IRGRP ) == -1) { // 440
        perror("chmod");
        exit(EXIT_FAILURE);
    }

    return 0;
}

I get the error chmod: Invalid argument

This code works fine on Linux. https://onlinegdb.com/d9KDZbl3H