SEMGET(2) | System Calls Manual | SEMGET(2) |
semget
—
#include <sys/sem.h>
int
semget
(key_t
key, int nsems,
int semflg);
semget
() system call returns the semaphore
identifier associated with key.
A new set containing nsems semaphores is
created if either key is equal to
IPC_PRIVATE
, or key does not
have a semaphore set associated with it and the
IPC_CREAT
bit is set in
semflg. If both the IPC_CREAT
bit and the IPC_EXCL
bit are set in
semflg, and key has a semaphore
set associated with it already, the operation will fail.
If a new set of semaphores is created, the data structure associated with it (the semid_ds structure, see semctl(2)) is initialized as follows:
semget
() returns a non-negative semaphore identifier if
successful. Otherwise, -1 is returned and errno is set
to reflect the error.
EACCES
]EEXIST
]IPC_CREAT
and
IPC_EXCL
are set in semflg,
and a semaphore set is already associated with
key.EINVAL
]A semaphore set associated with key exists, but has fewer semaphores than the number specified in nsems.
ENOSPC
]ENOENT
]IPC_CREAT
is not set in semflg and no semaphore set associated
with key was found.semget
system call conforms to
X/Open System Interfaces and Headers Issue 5
(“XSH5”).
May 13, 2004 | NetBSD 9.2 |