shm-4a.c

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

int main (void)
{
  int shm = shm_open ("test", O_CREAT | O_RDWR, 0666);
  char *buffer = mmap (NULL, 42, PROT_READ | PROT_WRITE, MAP_SHARED, shm, 0);
  strcpy (buffer, "Hello, world!");
  munmap (buffer, 42);
  close (shm);
  return 0;
}