What is the output of this program? #include #include #include #include int main() { int s_id; int *ptr; s_id = shm_open("shared_mem",O_CREAT|O_RDWR,0666); if(s_id == -1) perror("shm_open"); ptr = mmap(NULL,100,PROT_WRITE,MAP_PRIVATE,s_id,0); if(ptr == MAP_FAILED); perror("mmap"); ptr = mmap(ptr,100,PROT_WRITE,MAP_PRIVATE,s_id,0); if(ptr == MAP_FAILED); perror("mmap"); if(munmap(ptr,100) == -1) perror("munmap"); if(shm_unlink("shared_mem") == -1) perror("shm_unlink"); return 0; }