freebsd/lib/libsys/mq_unlink.2

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.\" Portions of this text are reprinted and reproduced in electronic form
.\" from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology --
.\" Portable Operating System Interface (POSIX), The Open Group Base
.\" Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of
.\" Electrical and Electronics Engineers, Inc and The Open Group.  In the
.\" event of any discrepancy between this version and the original IEEE and
.\" The Open Group Standard, the original IEEE and The Open Group Standard is
.\" the referee document.  The original Standard can be obtained online at
.\"	http://www.opengroup.org/unix/online.html.
.\"
.Dd February 15, 2021
.Dt MQ_UNLINK 2
.Os
.Sh NAME
.Nm mq_unlink
.Nd "mq_unlink - remove a message queue (REALTIME)"
.Sh LIBRARY
.Lb librt
.Sh SYNOPSIS
.In mqueue.h
.Ft int
.Fn mq_unlink "const char *name"
.Sh DESCRIPTION
The
.Fn mq_unlink
function removes the message queue named by the string
.Fa name .
If one or more processes have the message queue open when
.Fn mq_unlink
is called, destruction of the message queue will be postponed
until all references to the message queue have been closed.
However, the
.Fn mq_unlink
call need not block until all references have been closed; it may return
immediately.
.Pp
After a successful call to
.Fn mq_unlink ,
reuse of the name will subsequently cause
.Xr mq_open 2
to behave as if no message queue of this name exists.
.Sh RETURN VALUES
.Rv -std
.Sh ERRORS
The
.Fn mq_unlink
system call
will fail if:
.Bl -tag -width Er
.It Bq Er EACCESS
Permission is denied to unlink the message queue represented by
.Fa name .
.It Bq Er EINVAL
.Fa name
is invalid.
.It Bq Er ENAMETOOLONG
The length of the
.Fa name
argument exceeds
.Brq Dv PATH_MAX
or
a pathname component is longer than
.Brq Dv NAME_MAX .
.It Bq Er ENOENT
The message queue does not exist.
.It Bq Er ENOSYS
.Xr mqueuefs 4
module is neither loaded nor included in the kernel.
.El
.Sh SEE ALSO
.Xr mq_open 2
.Sh STANDARDS
The
.Fn mq_unlink
system call conforms to
.St -p1003.1-2004 .
The
.Bq Er EACCESS
error code is an extension to the standard.
.Sh HISTORY
Support for POSIX message queues first appeared in
.Fx 7.0 .
.Sh COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology --
Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
In the event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard is
the referee document.
The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html.