shmget(2) is used to obtain access to a shared memory segment. When the call succeeds, it returns the shared memory segment ID (shmid). The following code illustrates shmget(2).
#include <sys/types.h> #include <sys/ipc.h> #include <sys/shm.h> ... key_t key; /* key to be passed to shmget() */ int shmflg; /* shmflg to be passed to shmget() */ int shmid; /* return value from shmget() */ size_t size; /* size to be passed to shmget() */ ... key = ... size = ... shmflg) = ... if ((shmid = shmget (key, size, shmflg)) == –1) { perror("shmget: shmget failed"); exit(1); } else { (void) fprintf(stderr, "shmget: shmget returned %d\n", shmid); exit(0); } ...