What does this procedure do in a unix-like op?

Question

Command line

How can you describe the result of this procedure? I can't figure it out on my own.

key_t  key; int shmid;
if ((shmid =shmget (key, sizeof(Message), 0666|IPC_CREAT))<0)
{printf(“ error shmget \n”); _exit(1);}

Answer 1

Look here - Shared Memory.

Answer 2

Allocates a section of shared memory via shmget (), if it did not work out, writes an error.
man shmget You
could also google about System V shared memory