MSGGET(2) | System Calls Manual | MSGGET(2) |
msgget
— get
message queue
#include
<sys/msg.h>
int
msgget
(key_t
key, int
msgflg);
msgget
()
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 a new message queue is created, the data structure associated with it (the msqid_ds structure, see msgctl(2)) is initialized as follows:
MSGMNB
).Upon successful completion a positive message queue identifier is returned. Otherwise, -1 is returned and the global variable errno is set to indicate the error.
EACCES
]EEXIST
]IPC_CREAT
and
IPC_EXCL
are set in msgflg,
and a message queue is already associated with
key.ENOSPC
]ENOENT
]IPC_CREAT
was not set in msgflg and no message queue
associated with key was found.The msgget
() function conforms to the
X/Open System Interfaces option of IEEE Std 1003.1-2008
(“POSIX.1”).
Message queues first appeared in AT&T System V Release 1 UNIX and have been available since NetBSD 1.0.
July 18, 2019 | OpenBSD-current |