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Mdoc cleanup.

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This commit is contained in:
Mike Pritchard 1997-03-21 20:46:30 +00:00
parent 95522ed527
commit 9de8ddb8bc
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=24093
3 changed files with 91 additions and 43 deletions
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24
lib/libc/gen/msgget.3
View file

@ -46,15 +46,18 @@
returns the message queue identifier associated with
.Fa key .
A message queue identifier is a unique integer greater than zero.
.Pp
A message queue is created if either
.Fa key
is equal to IPC_PRIVATE, or
is equal to
.Dv IPC_PRIVATE ,
or
.Fa key
does not have a message queue identifier associated with it, and the IPC_CREAT
does not have a message queue identifier associated with it, and the
.Dv IPC_CREAT
bit is set in
.Fa msgflg.
.Pp
If a new message queue is created, the data structure associated with it (the
.Va msqid_ds
structure, see
@ -83,11 +86,11 @@ is set to the lower 9 bits of
.Va msg_rtime ,
and
.Va msg_stime
are set to 0
are set to 0.
.It
.Va msg_qbytes
is set to the system wide maximum value for the number of bytes in a queue
(MSGMNB).
.Pf ( Dv MSGMNB ) .
.It
.Va msg_ctime
is set to the current time.
@ -104,7 +107,11 @@ A message queue is already associated with
.Fa key
and the caller has no permission to access it.
.It Bq Er EEXIST
Both IPC_CREAT and IPC_EXCL are set in
Both
.Dv IPC_CREAT
and
.Dv IPC_EXCL
are set in
.Fa msgflg ,
and a message queue is already associated with
.Fa key .
@ -112,7 +119,8 @@ and a message queue is already associated with
A new message queue could not be created because the system limit for
the number of message queues has been reached.
.It Bq Er ENOENT
IPC_CREAT was not set in
.Dv IPC_CREAT
was not set in
.Fa msgflg
and no message queue associated with
.Fa key

68
lib/libc/gen/msgrcv.3
View file

@ -53,12 +53,13 @@ This structure should consist of the following members:
long mtype; /* message type */
char mtext[1]; /* body of message */
.Ed
.Pp
.Va mtype
is an integer greater than 0 that can be used for selecting messages,
.Va mtext
is an array of bytes, with a size up to that of the system limit (MSGMAX).
is an array of bytes, with a size up to that of the system limit
.Pf ( Dv MSGMAX ) .
.Pp
The value of
.Fa msgtyp
has one of the following meanings:
@ -78,26 +79,36 @@ less than or equal to the absolute value of
.Fa msgtyp
will be received.
.El
.Pp
.Fa msgsz
specifies the maximum length of the requested message. If the received
message has a length greater than
.Fa msgsz
it will be silently truncated if the MSG_NOERROR flag is set in
it will be silently truncated if the
.Dv MSG_NOERROR
flag is set in
.Fa msgflg ,
otherwise an error will be returned.
.Pp
If no matching message is present on the message queue specified by
.Fa msqid ,
the behavior of
.Fn msgrcv
depends on whether the IPC_NOWAIT flag is set in
depends on whether the
.Dv IPC_NOWAIT
flag is set in
.Fa msgflg
or not. If IPC_NOWAIT is set,
or not. If
.Dv IPC_NOWAIT
is set,
.Fn msgrcv
will immediately return a value of -1, and set
.Va errno
to EAGAIN. If IPC_NOWAIT is not set, the calling process will be blocked
to
.Er EAGAIN .
If
.Dv IPC_NOWAIT
is not set, the calling process will be blocked
until:
.Bl -bullet
.It
@ -105,13 +116,15 @@ A message of the requested type becomes available on the message queue.
.It
The message queue is removed, in which case -1 will be returned, and
.Va errno
set to EINVAL.
set to
.Er EINVAL .
.It
A signal is received and caught. -1 is returned, and
.Va errno
set to EINTR.
set to
.Er EINTR .
.El
.Pp
If a message is successfully received, the data structure associated with
.Fa msqid
is updated as follows:
@ -144,18 +157,20 @@ will fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
.Fa msqid
is not a valid message queue identifier
is not a valid message queue identifier.
.Pp
The message queue was removed while
.Fn msgrcv
was waiting for a message of the requested type to become available on it.
.Pp
.Fa msgsz
is less than 0.
.It Bq Er E2BIG
A matching message was received, but its size was greater than
.Fa msgsz
and the MSG_NOERROR flag was not set in
and the
.Dv MSG_NOERROR
flag was not set in
.Fa msgflg .
.It Bq Er EACCESS
The calling process does not have read access to the message queue.
@ -166,16 +181,27 @@ points to an invalid address.
The system call was interrupted by the delivery of a signal.
.It Bq Er EAGAIN
There is no message of the requested type available on the message queue,
and IPC_NOWAIT is set in
and
.Dv IPC_NOWAIT
is set in
.Fa msgflg .
.Sh SEE ALSO
.Xr msgctl 3 ,
.Xr msgget 3 ,
.Xr msgsnd 3
.Sh BUGS
NetBSD and FreeBSD do not define the EIDRM error value, which should be used in
the case of a removed message queue, nor the ENOMSG value, which
should be used when no suitable message is available and IPC_NOWAIT
.Tn NetBSD
and
.Tn FreeBSD
do not define the
.Er EIDRM
error value, which should be used in
the case of a removed message queue, nor the
.Er ENOMSG
value, which
should be used when no suitable message is available and
.Dv IPC_NOWAIT
is set.
.Sh HISTORY
Message queues appeared in the first release of AT&T Unix System V.
Message queues appeared in the first release of
AT&T Unix System V.

42
lib/libc/gen/msgsnd.3
View file

@ -53,17 +53,18 @@ consist of the following members:
long mtype; /* message type */
char mtext[1]; /* body of message */
.Ed
.Pp
.Va mtype
is an integer greater than 0 that can be used for selecting messages (see
.Xr msgrcv 3 ) ,
.Va mtext
is an array of bytes, with a size up to that of the system limit (MSGMAX).
is an array of bytes, with a size up to that of the system limit
.Pf ( Dv MSGMAX ) .
.Pp
If the number of bytes already on the message queue plus
.Fa msgsz
is bigger than the maximum number of bytes on the message queue (
.Va msg_qbytes ,
is bigger than the maximum number of bytes on the message queue
.Pf ( Va msg_qbytes ,
see
.Xr msgctl 3 ) ,
or the number of messages on all queues system-wide is already equal to
@ -73,9 +74,13 @@ determines the action of
.Fn msgsnd .
If
.Fa msgflg
has IPC_NOWAIT mask set in it, the call will return immediately. If
has
.Dv IPC_NOWAIT
mask set in it, the call will return immediately. If
.Fa msgflg
does not have IPC_NOWAIT set in it, the call will block until:
does not have
.Dv IPC_NOWAIT
set in it, the call will block until:
.Bl -bullet
.It
The condition which caused the call to block does no longer exist.
@ -83,13 +88,15 @@ The message will be sent.
.It
The message queue is removed, in which case -1 will be returned, and
.Va errno
is set to EINVAL.
is set to
.Er EINVAL .
.It
The caller catches a signal. The call returns with
.Va errno
set to EINTR.
set to
.Er EINTR .
.El
.Pp
After a successful call, the data structure associated with the message
queue is updated in the following way:
.Bl -bullet
@ -117,12 +124,12 @@ will fail if:
.It Bq Er EINVAL
.Fa msqid
is not a valid message queue identifier
.Pp
The message queue was removed while
.Fn msgsnd
was waiting for a resource to become available in order to deliver the
message.
.Pp
.Fa msgsz
is less than 0, or greater than
.Va msg_qbytes .
@ -130,7 +137,9 @@ is less than 0, or greater than
The calling process does not have write access to the message queue.
.It Bq Er EAGAIN
There was no space for this message either on the queue, or in the whole
system, and IPC_NOWAIT was set in
system, and
.Dv IPC_NOWAIT
was set in
.Fa msgflg .
.It Bq Er EFAULT
.Fa msgp
@ -139,7 +148,12 @@ points to an invalid address.
The system call was interrupted by the delivery of a signal.
.El
.Sh BUGS
NetBSD and FreeBSD do not define the EIDRM error value, which should be used
.Tn NetBSD
and
.Tn FreeBSD
do not define the
.Er EIDRM
error value, which should be used
in the case of a removed message queue.
.Sh HISTORY
Message queues appeared in the first release of AT&T Unix System V.