Add manuals for POSIX message queue.
This commit is contained in:
David Xu
parent
8d98402040
commit
968cc4bd61
@ -70,8 +70,10 @@ MAN+= _exit.2 accept.2 access.2 acct.2 adjtime.2 \
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kldunload.2 kqueue.2 kse.2 ktrace.2 link.2 lio_listio.2 listen.2 \
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lseek.2 \
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madvise.2 mincore.2 minherit.2 mkdir.2 mkfifo.2 mknod.2 mlock.2 \
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mlockall.2 mmap.2 modfind.2 modnext.2 modstat.2 mount.2 \
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mprotect.2 msync.2 munmap.2 nanosleep.2 ntp_adjtime.2 ntp_gettime.2 \
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mlockall.2 mmap.2 modfind.2 modnext.2 modstat.2 mount.2 mprotect.2 \
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mq_close.2 mq_getattr.2 mq_notify.2 mq_open.2 mq_receive.2 mq_send.2 \
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mq_setattr.2 \
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msync.2 munmap.2 nanosleep.2 ntp_adjtime.2 ntp_gettime.2 \
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nfssvc.2 open.2 pathconf.2 pipe.2 poll.2 profil.2 ptrace.2 quotactl.2 \
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read.2 readlink.2 reboot.2 recv.2 rename.2 revoke.2 rfork.2 rmdir.2 \
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rtprio.2 select.2 semctl.2 semget.2 semop.2 send.2 sendfile.2 \
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87
lib/libc/sys/mq_close.2
Normal file
87
lib/libc/sys/mq_close.2
Normal file
@ -0,0 +1,87 @@
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.\" Copyright (c) 2005 David Xu <davidxu@FreeBSD.org>
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice(s), this list of conditions and the following disclaimer as
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.\" the first lines of this file unmodified other than the possible
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.\" addition of one or more copyright notices.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice(s), this list of conditions and the following disclaimer in
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.\" the documentation and/or other materials provided with the
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.\" distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
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||||
.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
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.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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||||
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd November 29, 2005
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.Dt MQ_CLOSE 2
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.Os
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.Sh NAME
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.Nm mq_close
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.Nd "close a message queue (REALTIME)"
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In mqueue.h
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.Ft int
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.Fn mq_close "mqd_t mqdes"
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.Sh DESCRIPTION
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The
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.Fn mq_close
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syscall removes the association between the message queue descriptor,
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.Fa mqdes ,
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and its message queue. The results of using this message queue descriptor
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after successful return from this
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.Fn mq_close ,
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and until the return of this message queue descriptor from a subsequent
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.Fn mq_open ,
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are undefined.
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.Pp
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If the process has successfully attached a notification request to the
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message queue via this
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.Fa mqdes ,
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this attachment will be removed, and the message queue is available for
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another process to attach for notification.
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.Sh RETURN VALUES
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Upon successful completion, the
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.Fn mq_close
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syscall returns a value of zero; otherwise, the syscall returns a
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value of -1 and set
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.Va errno
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to indicate the error.
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.Sh ERRORS
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The
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.Fn mq_close
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system call
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will fail if:
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.Bl -tag -width Er
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.It Bq Er EBADF
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The
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.Fa mqdes
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argument is not a valid message queue descriptor.
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.El
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.Sh SEE ALSO
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.Xr mq_open 2 ,
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.Xr mq_unlink 2
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.Sh STANDARDS
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The
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.Fn mq_close
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system call conform to
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.St -p1003.1-2004 .
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.Sh HISTORY
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Support for POSIX message queue first appeared in
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.Fx 7.0 .
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107
lib/libc/sys/mq_getattr.2
Normal file
107
lib/libc/sys/mq_getattr.2
Normal file
@ -0,0 +1,107 @@
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.\" Copyright (c) 2005 David Xu <davidxu@FreeBSD.org>
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice(s), this list of conditions and the following disclaimer as
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.\" the first lines of this file unmodified other than the possible
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.\" addition of one or more copyright notices.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice(s), this list of conditions and the following disclaimer in
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.\" the documentation and/or other materials provided with the
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.\" distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
|
||||
.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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||||
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
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.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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||||
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd November 29, 2005
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.Dt MQ_CLOSE 2
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.Os
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.Sh NAME
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.Nm mq_getattr
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.Nd "get message queue attributes (REALTIME)"
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In mqueue.h
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.Ft int
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.Fn mq_getattr "mqd_t mqdes" "struct mq_attr *mqstat"
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.Sh DESCRIPTION
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The
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.Fn mq_getattr
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syscall obtains status information and attributes of the message queue and
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the open message queue description associated with the message queue
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descriptor.
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.Pp
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The
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.Fa mqdes
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argument specifies a message queue descriptor.
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.Pp
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The results are returned in the
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.Vt mq_attr
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structure referenced by the mqstat argument.
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.Pp
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Upon return, the following members will have the values associated with the
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open message queue description as set when the message queue was opened and
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as modified by subsequent
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.Fn mq_setattr
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calls:
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.Va mq_flags.
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.Pp
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The following attributes of the message queue will be returned as set at
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message queue creation:
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.Va mq_maxmsg ,
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.Va mq_msgsize .
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.Pp
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Upon return, the following members within the
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.Vt mq_attr
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structure referenced by the mqstat argument will be set to the current state
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of the message queue:
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.Pp
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.Bl -tag -width Er
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.It Va mq_flags
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The number of messages currently on the queue.
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.El
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.Sh RETURN VALUES
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Upon successful completion, the
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.Fn mq_getattr
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syscall returns zero. Otherwise, the syscall returns -1 and set
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.Va errno
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to indicate the error.
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.Sh ERRORS
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The
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.Fn mq_getattr
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syscall call
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will fail if:
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.Bl -tag -width Er
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.It Bq Er EBADF
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The
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.Fa mqdes
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argument is not a valid message queue descriptor.
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.El
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.Sh SEE ALSO
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.Xr mq_open 2 ,
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.Xr mq_send 2 ,
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.Xr mq_setattr 2 ,
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.Xr mq_timedsend 2 ,
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.Sh STANDARDS
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The
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.Fn mq_getattr
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system call conform to
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.St -p1003.1-2004 .
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.Sh HISTORY
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Support for POSIX message queue first appeared in
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.Fx 7.0 .
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103
lib/libc/sys/mq_notify.2
Normal file
103
lib/libc/sys/mq_notify.2
Normal file
@ -0,0 +1,103 @@
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.\" Copyright (c) 2005 David Xu <davidxu@FreeBSD.org>
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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||||
.\" notice(s), this list of conditions and the following disclaimer as
|
||||
.\" the first lines of this file unmodified other than the possible
|
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.\" addition of one or more copyright notices.
|
||||
.\" 2. Redistributions in binary form must reproduce the above copyright
|
||||
.\" notice(s), this list of conditions and the following disclaimer in
|
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.\" the documentation and/or other materials provided with the
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.\" distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
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.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
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.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
||||
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd November 29, 2005
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.Dt MQ_NOTIFY 2
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.Os
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.Sh NAME
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.Nm mq_notify
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.Nd "notify process that a message is available (REALTIME)"
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In mqueue.h
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.Ft int
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.Fn mq_notify "mqd_t mqdes" "const struct sigevent *notification"
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.Sh DESCRIPTION
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If the argument notification is not
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.Dv NULL ,
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this syscall will register the calling process to be notified of message
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arrival at an empty message queue associated with the specified message
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queue descriptor,
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.Fa mqdes.
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The notification specified by the notification argument will be sent to
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the process when the message queue transitions from empty to non-empty.
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At any time, only one process may be registered for notification by a
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message queue. If the calling process or any other process has already
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registered for notification of message arrival at the specified message
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queue, subsequent attempts to register for that message queue will fail.
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.Pp
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If notification is
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.Dv NULL
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and the process is currently registered for notification by the specified
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message queue, the existing registration will be removed.
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.Pp
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When the notification is sent to the registered process, its registration
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is removed. The message queue then is available for registration.
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.Pp
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If a process has registered for notification of message arrival at a
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message queue and some thread is blocked in
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.Fn mq_receive
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waiting to receive a message when a message arrives at the queue, the
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arriving message will satisfy the appropriate
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.Fn mq_receive .
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The resulting behavior is as if the message queue remains empty, and no
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notification will be sent.
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.Sh RETURN VALUES
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Upon successful completion, the
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.Fn mq_notify
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syscall returns a value of zero; otherwise, the function returns a value
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of -1 and set
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.Va errno
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to indicate the error.
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.Sh ERRORS
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The
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.Fn mq_notify
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syscall call
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will fail if:
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.Bl -tag -width Er
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.It Bq Er EBADF
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The
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.Fa mqdes
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argument is not a valid message queue descriptor.
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.It Bq Er EBUSY
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process is already registered for notification by the message queue.
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.El
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.Sh SEE ALSO
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.Xr mq_open 2 ,
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.Xr mq_send 2 ,
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.Xr mq_timedsend 2
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.Sh STANDARDS
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The
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.Fn mq_notify
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system call conform to
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.St -p1003.1-2004 .
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.Sh HISTORY
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Support for POSIX message queue first appeared in
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.Fx 7.0 .
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278
lib/libc/sys/mq_open.2
Normal file
278
lib/libc/sys/mq_open.2
Normal file
@ -0,0 +1,278 @@
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.\" Copyright (c) 2005 David Xu <davidxu@FreeBSD.org>
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
|
||||
.\" 1. Redistributions of source code must retain the above copyright
|
||||
.\" notice(s), this list of conditions and the following disclaimer as
|
||||
.\" the first lines of this file unmodified other than the possible
|
||||
.\" addition of one or more copyright notices.
|
||||
.\" 2. Redistributions in binary form must reproduce the above copyright
|
||||
.\" notice(s), this list of conditions and the following disclaimer in
|
||||
.\" the documentation and/or other materials provided with the
|
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.\" distribution.
|
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
|
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.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
||||
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
||||
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
|
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.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
|
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.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
|
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.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd November 29, 2005
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.Dt MQ_OPEN 2
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.Os
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.Sh NAME
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.Nm mq_open
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.Nd "open a message queue (REALTIME)"
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In mqueue.h
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.Ft mqd_t
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.Fn mq_open "const char *name" "int oflag" "..."
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.Sh DESCRIPTION
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The
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.Fn mq_open
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system call establishs the connection between a process and a message queue
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with a message queue descriptor. It creates an open message queue
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description that refers to the message queue, and a message queue descriptor
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that refers to that open message queue description. The message queue
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descriptor is used by other functions to refer to that message queue. The
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.Fa name
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argument points to a string naming a message queue. It is unspecified
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whether the name appears in the file system and is visible to other functions
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that take pathnames as arguments. The
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.Fa name
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argument conforms to the construction rules for a pathname. If
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.Fa name
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begins with the slash character, then processes calling
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.Fn mq_open
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with the same value of
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.Fa name
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refers to the same message queue object, as long as that name has not been
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removed. If
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.Fa name
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does not begin with the slash character, the effect is implementation-defined.
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The interpretation of slash characters other than the leading slash character
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in
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.Fa name
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is implementation-defined. If the
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.Fa name
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argument is not the name of an existing message queue and creation is not
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requested,
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.Fn mq_open
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will fail and returns an error.
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.Pp
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A message queue descriptor may be implemented using a file descriptor, in
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which case applications can open up to at least
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.Brq Dv OPEN_MAX
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file and message queues.
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.Pp
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The
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.Fa oflag
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argument requests the desired receive and/or send access to the message
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queue. The requested access permission to receive messages or send messages
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would be granted if the calling process would be granted read or write access,
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respectively, to an equivalently protected file.
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.Pp
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The value of
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.Fa oflag
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is the bitwise-inclusive OR of values from the following list.
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Applications should specify exactly one of the first three values (access
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modes) below in the value of
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.Fa oflag :
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.Bl -tag -width Er
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.It Bq Er O_RDONLY
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Open the message queue for receiving messages. The process can use the
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returned message queue descriptor with
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.Fn mq_receive ,
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but not
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.Fn mq_send .
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A message queue may be open multiple times in the same or different processes
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for receiving messages.
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.It Bq Er O_WRONLY
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Open the queue for sending messages. The process can use the returned
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message queue descriptor with
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.Fn mq_send
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but not
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.Fn mq_receive .
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A message queue may be open multiple times in the same or different processes
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for sending messages.
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.It Bq Er O_RDWR
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Open the queue for both receiving and sending messages. The process can use
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any of the functions allowed for
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.Dv O_RDONLY
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and
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.Dv O_WRONLY .
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A message queue may be open multiple times in the same or different processes
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for sending messages.
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.El
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.Pp
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Any combination of the remaining flags may be specified in the value of
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.Fa oflag :
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.Bl -tag -width Er
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.It Bq Er O_CREAT
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Create a message queue. It requires two additional arguments:
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.Fa mode ,
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which is of type
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.Vt mode_t ,
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and
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.Fa attr ,
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which is a pointer to an
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.Vt mq_attr
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structure. If the pathname
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.Fa name
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has already been used to create a message queue that still exists, then
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this flag has no effect, except as noted under
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.Dv O_EXCL .
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Otherwise, a message queue will be created without any messages
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in it. The user ID of the message queue will be set to the effective user ID
|
||||
of the process, and the group ID of the message queue will be set to the
|
||||
effective group ID of the process. The permission bits of the message queue
|
||||
will be set to the value of the
|
||||
.Fa mode
|
||||
argument, except those set in the file mode creation mask of the process.
|
||||
When bits in
|
||||
.Fa mode
|
||||
other than the file permission bits are specified, the effect is
|
||||
unspecified. If
|
||||
.Fa attr
|
||||
is
|
||||
.Dv NULL ,
|
||||
the message queue is created with implementation-defined default message
|
||||
queue attributes. If attr is non-NULL and the calling process has the
|
||||
appropriate privilege on name, the message queue mq_maxmsg and mq_msgsize
|
||||
attributes will be set to the values of the corresponding members in the
|
||||
.Vt mq_attr
|
||||
structure referred to by
|
||||
.Fa attr .
|
||||
If
|
||||
.Fa attr
|
||||
is non-NULL, but the calling process does not have the appropriate privilege
|
||||
on name, the
|
||||
.Fn mq_open
|
||||
function will fail and return an error without creating the message queue.
|
||||
.It Bq Er O_EXCL
|
||||
If
|
||||
.Dv O_EXCL
|
||||
and
|
||||
.Dv O_CREAT
|
||||
are set,
|
||||
.Fn mq_open
|
||||
will fail if the message queue name exists.
|
||||
.It Bq Er O_NONBLOCK
|
||||
Determines whether an
|
||||
.Fn mq_send
|
||||
or
|
||||
.Fn mq_receive
|
||||
waits for resources or messages that are not currently available, or fails
|
||||
with errno set to
|
||||
.Er EAGAIN ;
|
||||
see
|
||||
.Fn mq_send
|
||||
and
|
||||
.Fn mq_receive
|
||||
for details.
|
||||
.Pp
|
||||
The
|
||||
.Fn mq_open
|
||||
function does not add or remove messages from the queue.
|
||||
.Sh NOTES
|
||||
FreeBSD implements message queue based on file descriptor. The descriptor
|
||||
is inherited by child after
|
||||
.Fn fork .
|
||||
The descriptor is closed in new image after
|
||||
.Fn exec .
|
||||
.Fn select
|
||||
and
|
||||
.Fn kevent
|
||||
syscalls are supported for message queue descriptor.
|
||||
.Sh RETURN VALUES
|
||||
Upon successful completion, the function returns a message queue
|
||||
descriptor; otherwise, the function returns (mqd_t)-1 and set
|
||||
.Va errno
|
||||
to indicate the error.
|
||||
.Sh ERRORS
|
||||
The
|
||||
.Fn mq_open
|
||||
system call
|
||||
will fail if:
|
||||
.Bl -tag -width Er
|
||||
.It Bq Er EACCES
|
||||
The message queue exists and the permissions specified by
|
||||
.Fa oflag
|
||||
are denied, or the message queue does not exist and permission to create the
|
||||
message queue is denied
|
||||
.It Bq Er EEXIST
|
||||
.Dv O_CREAT
|
||||
and
|
||||
.Dv O_EXCL
|
||||
are set and the named message queue already exists.
|
||||
.It Bq Er EINTR
|
||||
The
|
||||
.Fn mq_open
|
||||
function was interrupted by a signal.
|
||||
.It Bq Er EINVAL
|
||||
The
|
||||
.Fn mq_open
|
||||
function is not supported for the given name.
|
||||
.It Bq Er EINVAL
|
||||
.Dv O_CREAT
|
||||
was specified in
|
||||
.Fa oflag ,
|
||||
the value of attr is not
|
||||
.Dv NULL ,
|
||||
and either
|
||||
.Va mq_maxmsg
|
||||
or
|
||||
.Va mq_msgsize
|
||||
was less than or equal to zero.
|
||||
.It Bq Er EMFILE
|
||||
Too many message queue descriptors or file descriptors are currently in use
|
||||
by this process.
|
||||
.It Bq Er ENAMETOOLONG
|
||||
The length of the name argument exceeds
|
||||
.Brq Dv PATH_MAX
|
||||
or a pathname component
|
||||
is longer than
|
||||
.Brq Dv NAME_MAX .
|
||||
.It Bq Er ENFILE
|
||||
Too many message queues are currently open in the system.
|
||||
.It Bq Er ENOENT
|
||||
.Dv O_CREAT
|
||||
is not set and the named message queue does not exist.
|
||||
.It Bq Er ENOSPC
|
||||
There is insufficient space for the creation of the new message queue.
|
||||
.El
|
||||
.Sh SEE ALSO
|
||||
.Xr mq_close 2 ,
|
||||
.Xr mq_getattr 2 ,
|
||||
.Xr mq_receive 2 ,
|
||||
.Xr mq_send 2 ,
|
||||
.Xr mq_setattr 2 ,
|
||||
.Xr mq_timedreceive 3 ,
|
||||
.Xr mq_timedsend 3
|
||||
.Xr mq_unlink 3
|
||||
.Sh STANDARDS
|
||||
The
|
||||
.Fn mq_open
|
||||
system call conform to
|
||||
.St -p1003.1-2004 .
|
||||
.Sh HISTORY
|
||||
Support for POSIX message queue first appeared in
|
||||
.Fx 7.0 .
|
||||
.Sh BUGS
|
||||
This implementation places strict requirements on the value of
|
||||
.Fa name :
|
||||
it must begin with a slash
|
||||
.Pq Ql / ,
|
||||
contain no other slash characters.
|
||||
190
lib/libc/sys/mq_receive.2
Normal file
190
lib/libc/sys/mq_receive.2
Normal file
@ -0,0 +1,190 @@
|
||||
.\" Copyright (c) 2005 David Xu <davidxu@FreeBSD.org>
|
||||
.\" All rights reserved.
|
||||
.\"
|
||||
.\" Redistribution and use in source and binary forms, with or without
|
||||
.\" modification, are permitted provided that the following conditions
|
||||
.\" are met:
|
||||
.\" 1. Redistributions of source code must retain the above copyright
|
||||
.\" notice(s), this list of conditions and the following disclaimer as
|
||||
.\" the first lines of this file unmodified other than the possible
|
||||
.\" addition of one or more copyright notices.
|
||||
.\" 2. Redistributions in binary form must reproduce the above copyright
|
||||
.\" notice(s), this list of conditions and the following disclaimer in
|
||||
.\" the documentation and/or other materials provided with the
|
||||
.\" distribution.
|
||||
.\"
|
||||
.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
|
||||
.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
||||
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
||||
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
|
||||
.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
||||
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
||||
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
|
||||
.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
|
||||
.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
|
||||
.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
|
||||
.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||||
.\"
|
||||
.\" $FreeBSD$
|
||||
.\"
|
||||
.Dd November 29, 2005
|
||||
.Dt MQ_SEND 2
|
||||
.Os
|
||||
.Sh NAME
|
||||
.Nm mq_receive , mq_timedreceive
|
||||
.Nd "receive a message from message queue (REALTIME)"
|
||||
.Sh LIBRARY
|
||||
.Lb libc
|
||||
.Sh SYNOPSIS
|
||||
.In mqueue.h
|
||||
.Ft ssize_t
|
||||
.Fo mq_receive
|
||||
.Fa "mqd_t mqdes"
|
||||
.Fa "char *msg_ptr"
|
||||
.Fa "size_t msg_len"
|
||||
.Fa "unsigned *msg_prio"
|
||||
.Fc
|
||||
.Ft ssize_t
|
||||
.Fo mq_timereceive
|
||||
.Fa "mqd_t mqdes"
|
||||
.Fa "char *msg_ptr"
|
||||
.Fa "size_t msg_len"
|
||||
.Fa "unsigned *msg_prio"
|
||||
.Fa "const struct timespec *abs_timeout"
|
||||
.Fc
|
||||
.Sh DESCRIPTION
|
||||
The
|
||||
.Fn mq_receive
|
||||
syscall receives oldest of the highest priority message(s) from the
|
||||
message queue specified by
|
||||
.Fa mqdes .
|
||||
If the size of the buffer in bytes, specified by the
|
||||
.Fa msg_len
|
||||
argument, is less than the
|
||||
.Fa mq_msgsize
|
||||
attribute of the message queue, the syscall will fail and return an
|
||||
error. Otherwise, the selected message will be removed from the queue
|
||||
and copied to the buffer pointed to by the
|
||||
.Fa msg_ptr
|
||||
argument.
|
||||
.Pp
|
||||
If the value of
|
||||
.Fa msg_len
|
||||
is greater than
|
||||
.Brq Dv SSIZE_MAX ,
|
||||
the result is implementation-defined.
|
||||
.Pp
|
||||
If the argument
|
||||
.Fa msg_prio
|
||||
is not NULL, the priority of the selected message will be stored in the
|
||||
location referenced by
|
||||
.Fa msg_prio .
|
||||
If the specified message queue is empty and
|
||||
.Dv O_NONBLOCK
|
||||
is not set in the message queue description associated with
|
||||
.Fa mqdes ,
|
||||
.Fn mq_receive
|
||||
will block until a message is enqueued on the message queue or until
|
||||
.Fn mq_receive
|
||||
is interrupted by a signal. If more than one thread is waiting to receive
|
||||
a message when a message arrives at an empty queue and the Priority
|
||||
Scheduling option is supported, then the thread of highest priority that
|
||||
has been waiting the longest will be selected to receive the message.
|
||||
Otherwise, it is unspecified which waiting thread receives the message.
|
||||
If the specified message queue is empty and
|
||||
.Dv O_NONBLOCK
|
||||
is set in the message queue description associated with mqdes, no message
|
||||
will be removed from the queue, and
|
||||
.Fn mq_receive
|
||||
will return an error.
|
||||
.Pp
|
||||
The
|
||||
.Fn mq_timedreceive
|
||||
syscall will receive the oldest of the highest priority messages from the
|
||||
message queue specified by
|
||||
.Fa mqdes
|
||||
as described for the
|
||||
.Fn mq_receive
|
||||
syscall. However, if
|
||||
.Dv O_NONBLOCK
|
||||
was not specified when the message queue was opened via the
|
||||
.Fn mq_open
|
||||
syscall, and no message exists on the queue to satisfy the receive, the wait
|
||||
for such a message will be terminated when the specified timeout expires. If
|
||||
.Dv O_NONBLOCK
|
||||
is set, this syscall is equivalent to
|
||||
.Fn mq_receive .
|
||||
.Pp
|
||||
The timeout expires when the absolute time specified by
|
||||
.Fa abs_timeout
|
||||
passes, as measured by the clock on which timeouts are based (that is, when
|
||||
the value of that clock equals or exceeds
|
||||
.Fa abs_timeout ) ,
|
||||
or if the absolute time specified by
|
||||
.Fa abs_timeout
|
||||
has already been passed at the time of the call.
|
||||
.Pp
|
||||
The timeout is based on the CLOCK_REALTIME clock.
|
||||
.Pp
|
||||
.Sh RETURN VALUES
|
||||
Upon successful completion, the
|
||||
.Fn mq_receive
|
||||
and
|
||||
.Fn mq_timedreceive
|
||||
syscalls return the length of the selected message in bytes and the
|
||||
message is removed from the queue. Otherwise, no message is removed
|
||||
from the queue, the syscalls returns a value of -1, and set
|
||||
.Va errno
|
||||
to indicate the error.
|
||||
.Sh ERRORS
|
||||
The
|
||||
.Fn mq_receive
|
||||
and
|
||||
.Fn mq_timedreceive
|
||||
system calls
|
||||
will fail if:
|
||||
.Bl -tag -width Er
|
||||
.It Bq Er EAGAIN
|
||||
.Dv O_NONBLOCK
|
||||
flag is set in the message queue description associated with
|
||||
.Fa mqdes ,
|
||||
and the specified message queue is empty.
|
||||
.It Bq Er EBADF
|
||||
The
|
||||
.Fa mqdes
|
||||
argument is not a valid message queue descriptor open for reading.
|
||||
.It Bq Er EMSGSIZE
|
||||
The specified message buffer size,
|
||||
.Fa msg_len ,
|
||||
is less than the message size attribute of the message queue.
|
||||
.It Bq Er EINTR
|
||||
The
|
||||
.Fn mq_receive
|
||||
or
|
||||
.Fn mq_timedreceive
|
||||
operation was interrupted by a signal.
|
||||
.It Bq Er EINVAL
|
||||
The process or thread would have blocked, and the
|
||||
.Fa abs_timeout
|
||||
parameter specified a nanoseconds field value less than zero or greater
|
||||
than or equal to 1000 million.
|
||||
.It Bq Er ETIMEDOUT
|
||||
The
|
||||
.Dv O_NONBLOCK
|
||||
flag was not set when the message queue was opened, but no message arrived
|
||||
on the queue before the specified timeout expired.
|
||||
.El
|
||||
.Sh SEE ALSO
|
||||
.Xr mq_open 2 ,
|
||||
.Xr mq_send 2 ,
|
||||
.Xr mq_timesend 2
|
||||
.Sh STANDARDS
|
||||
The
|
||||
.Fn mq_receive
|
||||
and
|
||||
.Fn mq_timereceive
|
||||
system calls conform to
|
||||
.St -p1003.1-2004 .
|
||||
.Sh HISTORY
|
||||
Support for POSIX message queue first appeared in
|
||||
.Fx 7.0 .
|
||||
204
lib/libc/sys/mq_send.2
Normal file
204
lib/libc/sys/mq_send.2
Normal file
@ -0,0 +1,204 @@
|
||||
.\" Copyright (c) 2005 David Xu <davidxu@FreeBSD.org>
|
||||
.\" All rights reserved.
|
||||
.\"
|
||||
.\" Redistribution and use in source and binary forms, with or without
|
||||
.\" modification, are permitted provided that the following conditions
|
||||
.\" are met:
|
||||
.\" 1. Redistributions of source code must retain the above copyright
|
||||
.\" notice(s), this list of conditions and the following disclaimer as
|
||||
.\" the first lines of this file unmodified other than the possible
|
||||
.\" addition of one or more copyright notices.
|
||||
.\" 2. Redistributions in binary form must reproduce the above copyright
|
||||
.\" notice(s), this list of conditions and the following disclaimer in
|
||||
.\" the documentation and/or other materials provided with the
|
||||
.\" distribution.
|
||||
.\"
|
||||
.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
|
||||
.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
||||
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
||||
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
|
||||
.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
||||
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
||||
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
|
||||
.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
|
||||
.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
|
||||
.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
|
||||
.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||||
.\"
|
||||
.\" $FreeBSD$
|
||||
.\"
|
||||
.Dd November 29, 2005
|
||||
.Dt MQ_SEND 2
|
||||
.Os
|
||||
.Sh NAME
|
||||
.Nm mq_send , mq_timedsend
|
||||
.Nd "send a message to message queue (REALTIME)"
|
||||
.Sh LIBRARY
|
||||
.Lb libc
|
||||
.Sh SYNOPSIS
|
||||
.In mqueue.h
|
||||
.Ft int
|
||||
.Fo mq_send
|
||||
.Fa "mqd_t mqdes"
|
||||
.Fa "const char *msg_ptr"
|
||||
.Fa "size_t msg_len"
|
||||
.Fa "unsigned msg_prio"
|
||||
.Fc
|
||||
.Ft int
|
||||
.Fo mq_timesend
|
||||
.Fa "mqd_t mqdes"
|
||||
.Fa "const char *msg_ptr"
|
||||
.Fa "size_t msg_len"
|
||||
.Fa "unsigned msg_prio"
|
||||
.Fa "const struct timespec *abs_timeout"
|
||||
.Fc
|
||||
.Sh DESCRIPTION
|
||||
The
|
||||
.Fn mq_send
|
||||
syscall adds the message pointed to by the argument
|
||||
.Fa msg_ptr
|
||||
to the message queue specified by
|
||||
.Fa mqdes .
|
||||
The
|
||||
.Fa msg_len
|
||||
argument specifies the length of the message, in bytes, pointed to by
|
||||
.Fa msg_ptr .
|
||||
The value of
|
||||
.Fa msg_len
|
||||
should be less than or equal to the
|
||||
.Fa mq_msgsize
|
||||
attribute of the message queue, or
|
||||
.Fn mq_send
|
||||
will fail.
|
||||
.Pp
|
||||
If the specified message queue is not full,
|
||||
.Fn mq_send
|
||||
will behave as if the message is inserted into the message queue at
|
||||
the position indicated by the
|
||||
.Fa msg_prio
|
||||
argument. A message with a larger numeric value of
|
||||
.Fa msg_prio
|
||||
will be inserted before messages with lower values of
|
||||
.Fa msg_prio .
|
||||
A message will be inserted after other messages in the queue, if any,
|
||||
with equal
|
||||
.Fa msg_prio .
|
||||
The value of
|
||||
.Fa msg_prio
|
||||
should be less than
|
||||
.Brq Dv MQ_PRIO_MAX .
|
||||
.Pp
|
||||
If the specified message queue is full and
|
||||
.Dv O_NONBLOCK
|
||||
is not set in the message queue description associated with
|
||||
.Fa mqdes ,
|
||||
.Fn mq_send
|
||||
will block until space becomes available to enqueue the
|
||||
message, or until
|
||||
.Fn mq_send
|
||||
is interrupted by a signal. If more than one thread is
|
||||
waiting to send when space becomes available in the message queue and
|
||||
the Priority Scheduling option is supported, then the thread of the
|
||||
highest priority that has been waiting the longest will be unblocked
|
||||
to send its message. Otherwise, it is unspecified which waiting thread
|
||||
is unblocked. If the specified message queue is full and
|
||||
.Dv O_NONBLOCK
|
||||
is set in the message queue description associated with
|
||||
.Fa mqdes ,
|
||||
the message will not be queued and
|
||||
.Fn mq_send
|
||||
will return an error.
|
||||
.Pp
|
||||
The
|
||||
.Fn mq_timedsend
|
||||
syscall will add a message to the message queue specified by
|
||||
.Fa mqdes
|
||||
in the manner defined for the
|
||||
.Fn mq_send
|
||||
syscall. However, if the specified message queue is full and
|
||||
.Dv O_NONBLOCK
|
||||
is not set in the message queue description associated with
|
||||
.Fa mqdes ,
|
||||
the wait for sufficient room in the queue will be terminated when
|
||||
the specified timeout expires. If
|
||||
.Dv O_NONBLOCK
|
||||
is set in the message queue description, this syscall is
|
||||
equivalent to
|
||||
.Fn mq_send .
|
||||
.Pp
|
||||
The timeout will expire when the absolute time specified by
|
||||
.Fa abs_timeout
|
||||
passes, as measured by the clock on which timeouts are based (that is,
|
||||
when the value of that clock equals or exceeds
|
||||
.Fa abs_timeout ) ,
|
||||
or if the absolute time specified by
|
||||
.Fa abs_timeout
|
||||
has already been passed at the time of the call.
|
||||
.Pp
|
||||
The timeout is based on the CLOCK_REALTIME clock.
|
||||
.Sh RETURN VALUES
|
||||
Upon successful completion, the
|
||||
.Fn mq_send
|
||||
and
|
||||
.Fn mq_timedsend
|
||||
syscalls return a value of zero. Otherwise, no message will be
|
||||
enqueued, the syscalls returns -1, and
|
||||
.Va errno
|
||||
is set to indicate the error.
|
||||
.Sh ERRORS
|
||||
The
|
||||
.Fn mq_send
|
||||
and
|
||||
.Fn mq_timedsend
|
||||
system calls
|
||||
will fail if:
|
||||
.Bl -tag -width Er
|
||||
.It Bq Er EAGAIN
|
||||
The
|
||||
.Dv O_NONBLOCK
|
||||
flag is set in the message queue description associated with
|
||||
.Fa mqdes ,
|
||||
and the specified message queue is full.
|
||||
.It Bq Er EBADF
|
||||
The
|
||||
.Fa mqdes
|
||||
argument is not a valid message queue descriptor open for writing.
|
||||
.It Bq Er EINTR
|
||||
A signal interrupted the call to
|
||||
.Fn mq_send
|
||||
or
|
||||
.Fn mq_timedsend.
|
||||
.It Bq Er EINVAL
|
||||
The value of
|
||||
.Fa msg_prio
|
||||
was outside the valid range.
|
||||
.It Bq Er EINVAL
|
||||
The process or thread would have blocked, and the
|
||||
.Fa abs_timeout
|
||||
parameter specified a nanoseconds field value less than zero or greater
|
||||
than or equal to 1000 million.
|
||||
.It Bq Er EMSGSIZE
|
||||
The specified message length,
|
||||
.Fa msg_len ,
|
||||
exceeds the message size attribute of the message queue.
|
||||
.It Bq Er ETIMEDOUT
|
||||
The
|
||||
.Dv O_NONBLOCK
|
||||
flag was not set when the message queue was opened, but the timeout
|
||||
expired before the message could be added to the queue.
|
||||
.El
|
||||
.Sh SEE ALSO
|
||||
.Xr mq_open 2 ,
|
||||
.Xr mq_receive 2 ,
|
||||
.Xr mq_setattr 2 ,
|
||||
.Xr mq_timereceive 2
|
||||
.Sh STANDARDS
|
||||
The
|
||||
.Fn mq_send
|
||||
and
|
||||
.Fn mq_timesend
|
||||
system calls conform to
|
||||
.St -p1003.1-2004 .
|
||||
.Sh HISTORY
|
||||
Support for POSIX message queue first appeared in
|
||||
.Fx 7.0 .
|
||||
104
lib/libc/sys/mq_setattr.2
Normal file
104
lib/libc/sys/mq_setattr.2
Normal file
@ -0,0 +1,104 @@
|
||||
.\" Copyright (c) 2005 David Xu <davidxu@FreeBSD.org>
|
||||
.\" All rights reserved.
|
||||
.\"
|
||||
.\" Redistribution and use in source and binary forms, with or without
|
||||
.\" modification, are permitted provided that the following conditions
|
||||
.\" are met:
|
||||
.\" 1. Redistributions of source code must retain the above copyright
|
||||
.\" notice(s), this list of conditions and the following disclaimer as
|
||||
.\" the first lines of this file unmodified other than the possible
|
||||
.\" addition of one or more copyright notices.
|
||||
.\" 2. Redistributions in binary form must reproduce the above copyright
|
||||
.\" notice(s), this list of conditions and the following disclaimer in
|
||||
.\" the documentation and/or other materials provided with the
|
||||
.\" distribution.
|
||||
.\"
|
||||
.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
|
||||
.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
||||
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
||||
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
|
||||
.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
||||
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
||||
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
|
||||
.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
|
||||
.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
|
||||
.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
|
||||
.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||||
.\"
|
||||
.\" $FreeBSD$
|
||||
.\"
|
||||
.Dd November 29, 2005
|
||||
.Dt MQ_CLOSE 2
|
||||
.Os
|
||||
.Sh NAME
|
||||
.Nm mq_setattr
|
||||
.Nd "set message queue attributes (REALTIME)"
|
||||
.Sh LIBRARY
|
||||
.Lb libc
|
||||
.Sh SYNOPSIS
|
||||
.In mqueue.h
|
||||
.Ft int
|
||||
.Fo mq_setattr
|
||||
.Fa "mqd_t mqdes"
|
||||
.Fa "struct mq_attr *restrict mqstat"
|
||||
.Fa "struct mq_attr *restrict omqstat"
|
||||
.Fc
|
||||
.Sh DESCRIPTION
|
||||
The
|
||||
.Fn mq_setattr
|
||||
syscall sets attributes associated with the open message queue description
|
||||
referenced by the message queue descriptor specified by
|
||||
.Fa mqdes .
|
||||
The message queue attributes corresponding to the following members defined
|
||||
in the
|
||||
.Vt mq_attr
|
||||
structure will be set to the specified values upon successful completion of
|
||||
.Fn mq_setattr :
|
||||
.Pp
|
||||
.Bl -tag -width Er
|
||||
.It Va mq_flags
|
||||
The value of this member is the bitwise-logical OR of zero or more of
|
||||
.Dv O_NONBLOCK
|
||||
and any implementation-defined flags.
|
||||
.El
|
||||
.Pp
|
||||
The values of the
|
||||
.Va mq_maxmsg ,
|
||||
.Va mq_msgsize ,
|
||||
and
|
||||
.Va mq_curmsgs
|
||||
embers of the
|
||||
.Vt mq_attr
|
||||
structure are ignored by
|
||||
.Fn mq_setattr .
|
||||
.Sh RETURN VALUES
|
||||
Upon successful completion, the function returns a value of zero and the
|
||||
attributes of the message queue will have been changed as specified.
|
||||
.Pp
|
||||
Otherwise, the message queue attributes are unchanged, and the function
|
||||
returns a value of -1 and set
|
||||
.Va errno
|
||||
to indicate the error.
|
||||
.Sh ERRORS
|
||||
The
|
||||
.Fn mq_setattr
|
||||
syscall call
|
||||
will fail if:
|
||||
.Bl -tag -width Er
|
||||
.It Bq Er EBADF
|
||||
The
|
||||
.Fa mqdes
|
||||
argument is not a valid message queue descriptor.
|
||||
.El
|
||||
.Sh SEE ALSO
|
||||
.Xr mq_open 2 ,
|
||||
.Xr mq_send 2 ,
|
||||
.Xr mq_timedsend 2 ,
|
||||
.Sh STANDARDS
|
||||
The
|
||||
.Fn mq_setattr
|
||||
system call conform to
|
||||
.St -p1003.1-2004 .
|
||||
.Sh HISTORY
|
||||
Support for POSIX message queue first appeared in
|
||||
.Fx 7.0 .
|
||||
Loading…
Reference in New Issue
Block a user