int
msgget(
key_t key
, int msgflg
)
)
system call returns the message queue identifier associated with
key
.
A message queue identifier is a unique integer greater than zero.
A message queue is created if either
key
is equal to
IPC_PRIVATE
,
or
key
does not have a message queue identifier associated with it and the
IPC_CREAT
bit is set in
msgflg
.
If both the
IPC_CREAT
bit and the
IPC_EXCL
bit are set in
msgflg
,
and
key
has a message queue identifier associated with it already,
the operation will fail.
If a new message queue is created, the data structure associated with it (the msqid_ds structure, see msgctl(2)) is initialized as follows:
msgflg
.
MSGMNB
).
EACCES
]
key
and the caller has no permission to access it.
EEXIST
]
IPC_CREAT
and
IPC_EXCL
are set in
msgflg
,
and a message queue is already associated with
key
.
ENOSPC
]
ENOENT
]
IPC_CREAT
is not set in
msgflg
and no message queue associated with
key
was found.
AT&T
System V UNIX
.