msgctl.2 (2010 09)

msgctl(2) msgctl(2)

[EINVAL] msqid is not a valid message queue identiﬁer.

[EINVAL] cmd is not a valid command, or the command contains invalid parameters.

[EACCES] cmd is equal to

IPC_STAT and Read operation permission is denied to the calling pro-

cess (see message operation permissions in glossary (9)).

[EPERM] cmd is equal to

IPC_RMID or IPC_SET

and the calling process does not have the

OWNER privilege or the effective user ID of the calling process is not equal to the value of

either msg_perm.uid or msg_perm.cuid

in the data structure associated with

msqid.

[EPERM] cmd is equal to

IPC_SET, an attempt is being made to increase to the value of

msg_qbytes, and the user does not have the

LIMIT privilege.

[EFAULT] buf points to an illegal address. Reliable detection of this error is implementation depen-

dent.