perldoc > semget(2)

    semget KEY,NSEMS,FLAGS
            Calls the System V IPC function semget(2). Returns the semaphore
            id, or the undefined value on error. See also "SysV IPC" in
            perlipc and the documentation for "IPC::SysV" and
            "IPC::Semaphore".

            Portability issues: "semget" in perlport.