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unix 下的C开发手册,还用详细的例程。

operation.

<dt><b>-</b><dd>If the above is not true.

</dl>
<p>
The second character is:
<dl compact>

<dt><b>R</b><dd>If a process is waiting on a
<i><a href="../xsh/msgrcv.html">msgrcv()</a></i>
operation.

<dt><b>C</b>&nbsp;or&nbsp;<b>-</b><dd>If the associated shared memory segment is to be cleared
when the first attach operation is executed.

<dt><b>-</b><dd>If none of the above is true.

</dl>
<p>
The next nine characters are interpreted as three sets of three
bits each.
The first set refers to the owner's permissions; the next
to permissions of others in the usergroup of the facility entry;
and the last to all others.
Within each set, the first character indicates permission to read,
the second character indicates permission to write or alter
the facility entry, and the last character is a minus sign (-).
<p>
The permissions are indicated as follows:
<dl compact>

<dt><b>r</b><dd>If read permission is granted.

<dt><b>w</b><dd>If write permission is granted.

<dt><b>a</b><dd>If alter permission is granted.

<dt><b>-</b><dd>If the indicated permission is not granted.

</dl>
<p>
The first character following the permissions specifies if
there is an alternate or additional access control method associated
with the facility.
If there is no alternate or additional access control method
associated with the facility, a single space character
will be written; otherwise another printable
character will be written.
<p>
<dt>OWNER	(all)<dd>The user name of the owner of the facility entry.
If the user name of the owner is found in the user database,
at least the first eight column positions of the name are written using
the format "%s".
Otherwise, the user ID of the owner is written using the format "%d".
<p>
<dt>GROUP	(all)<dd>The group name of the owner of the facility entry.
If the group name of the owner is found in the group database,
at least the first eight column positions of the name are written using
the format "%s".
Otherwise, the group ID of the owner is written using the format "%d".
<p>
</dl>
<p>
The following nine columns are only written out for message
queues:
<dl compact>

<dt>CREATOR	(<b>a</b>,<b>c</b>)<dd>The user name of the creator of the facility entry.
If the user name of the creator is found in the user database,
at least the first eight column positions of the name are written
using the format "%s".
Otherwise, the user ID of the creator is written using the format "%d".

<dt>CGROUP	(<b>a</b>,<b>c</b>)<dd>The group name of the creator of the facility entry.
If the group name of the creator is found in the group database,
at least the first eight column positions of the name are written
using the format "%s".
Otherwise, the group ID of the creator is written using the format "%d".

<dt>CBYTES	(<b>a</b>,<b>o</b>)<dd>The number of bytes in messages currently outstanding on the
associated message queue.
This field is written using the format "%d".

<dt>QNUM	(<b>a</b>,<b>o</b>)<dd>The number of messages currently outstanding
on the associated message queue.
This field is written using the format "%d".

<dt>QBYTES	(<b>a</b>,<b>b</b>)<dd>The maximum number of bytes allowed in messages outstanding on
the associated message queue.
This field is written using the format "%d".

<dt>LSPID	(<b>a</b>,<b>p</b>)<dd>The process ID of the last process to send a message to the
associated queue.
This field is written using the format:
<pre>
<code>
"%d", &lt;<i>pid</i>&gt;
</code>
</pre>

where &lt;<i>pid</i>&gt; is 0 if no message has been sent
to the corresponding message queue; otherwise,
&lt;<i>pid</i>&gt; is the process ID of the last process to
send a message to the queue.

<dt>LRPID	(<b>a</b>,<b>p</b>)<dd>The process ID of the last process to
receive a message from the associated queue.
This field is written using the format:
<pre>
<code>
"%d", &lt;<i>pid</i>&gt;
</code>
</pre>

where &lt;<i>pid</i>&gt; is 0 if no message has been
received from the corresponding message queue;
otherwise, &lt;<i>pid</i>&gt; is the process ID of the last
process to receive a message from the queue.

<dt>STIME	(<b>a</b>,<b>t</b>)<dd>The time the last message was sent to the associated queue.
If a message has been sent to the corresponding message queue,
the hour, minute and second of the last time a message
was sent to the queue is written using the format "%d:%2.2d:%2.2d".
Otherwise, the format " no-entry" will be written.

<dt>RTIME	(<b>a</b>,<b>t</b>)<dd>The time the last message was received from the associated queue.
If a message has been received from the corresponding message queue,
the hour, minute and second of the last time a message was received
from the queue is written using the format "%d:%2.2d:%2.2d".
Otherwise, the format " no-entry" will be written.

</dl>
<br>
<p>
The following eight columns are only written out for shared
memory segments.
<dl compact>

<dt>CREATOR	(<b>a</b>,<b>c</b>)<dd>The user name of the creator of the facility entry.
If the user name of the creator is found in the user database,
at least the first eight column positions of the name are written
using the format "%s".
Otherwise, the user ID of the creator is written using the format "%d".

<dt>CGROUP	(<b>a</b>,<b>c</b>)<dd>The group name of the creator of the facility entry.
If the group name of the creator is found in the group database,
at least the first eight column positions of the name are written
using the format "%s".
Otherwise, the group ID of the creator is written using the format "%d".


<dt>NATTCH	(<b>a</b>,<b>o</b>)<dd>The number of processes attached to the
associated shared memory segment.
This field is written using the format "%d".

<dt>SEGSZ	(<b>a</b>,<b>b</b>)<dd>The size of the associated shared memory segment.
This field is written using the format "%d".

<dt>CPID	(<b>a</b>,<b>p</b>)<dd>The process ID of the creator of the shared memory entry.
This field is written using the format "%d".

<dt>LPID	(<b>a</b>,<b>p</b>)<dd>The process ID of the last process to attach
or detach the shared memory segment.
This field is written using the format:
<pre>
<code>
"%d", &lt;<i>pid</i>&gt;
</code>
</pre>

where &lt;<i>pid</i>&gt; is 0 if no process has attached
the corresponding shared memory segment;
otherwise, &lt;<i>pid</i>&gt; is the process ID of the
last process to attach or detach the segment.

<dt>ATIME	(<b>a</b>,<b>t</b>)<dd>The time the last attach on the associated
shared memory segment was completed.
If the corresponding shared memory segment
has ever been attached, the hour, minute
and second of the last time the segment was
attached is written using the format "%d:%2.2d:%2.2d".
Otherwise, the format " no-entry" will be written.

<dt>DTIME	(<b>a</b>,<b>t</b>)<dd>The time the last detach on the associated
shared memory segment was completed.
If the corresponding shared memory segment
has ever been detached, the hour, minute,
and second of the last time the segment was
detached is written using the format "%d:%2.2d:%2.2d".
Otherwise, the format " no-entry" will be written.

</dl>
<p>
The following four columns are only written out for semaphore sets:
<dl compact>

<dt>CREATOR	(<b>a</b>,<b>c</b>)<dd>The user name of the creator of the facility entry.
If the user name of the creator is found in the user database,
at least the first eight column positions of the name are written
using the format "%s".
Otherwise, the user ID of the creator is written using the format "%d".

<dt>CGROUP	(<b>a</b>,<b>c</b>)<dd>The group name of the creator of the facility entry.
If the group name of the creator is found in the group database,
at least the first eight column positions of the name are written
using the format "%s".
Otherwise, the group ID of the creator is written using the format "%d".


<dt>NSEMS	(<b>a</b>,<b>t</b>)<dd>The number of semaphores in the set associated
with the semaphore entry.
This field is written using the format "%d".

<dt>OTIME	(<b>a</b>,<b>t</b>)<dd>The time the last semaphore operation on the
set associated with the semaphore entry was completed.
If a semaphore operation has ever been performed on the
corresponding semaphore set, the hour, minute and second of the last
semaphore operation on the semaphore set
is written using the format "%d:%2.2d:%2.2d".
Otherwise, the format " no-entry" will be written.

</dl>
<p>
The following column is written for all three reports when
it is requested:
<dl compact>

<dt>CTIME	(<b>a</b>,<b>t</b>)<dd>The time the associated entry was created or changed.
The hour, minute and second of the time when the associated entry
was created are written using the format "%d:%2.2d:%2.2d".

</dl>
</blockquote><h4><a name = "tag_001_014_1014">&nbsp;</a>STDERR</h4><blockquote>
Used only for diagnostic messages.
</blockquote><h4><a name = "tag_001_014_1015">&nbsp;</a>OUTPUT FILES</h4><blockquote>
None.
</blockquote><h4><a name = "tag_001_014_1016">&nbsp;</a>EXTENDED DESCRIPTION</h4><blockquote>
None.
</blockquote><h4><a name = "tag_001_014_1017">&nbsp;</a>EXIT STATUS</h4><blockquote>
The following exit values are returned:
<dl compact>

<dt> 0<dd>Successful completion.

<dt>&gt;0<dd>An error occurred.

</dl>
</blockquote><h4><a name = "tag_001_014_1018">&nbsp;</a>CONSEQUENCES OF ERRORS</h4><blockquote>
Default.
</blockquote><h4><a name = "tag_001_014_1019">&nbsp;</a>APPLICATION USAGE</h4><blockquote>
Things can change while
<i>ipcs</i>
is running; the information it gives is guaranteed to be accurate
only when it was retrieved.
</blockquote><h4><a name = "tag_001_014_1020">&nbsp;</a>EXAMPLES</h4><blockquote>
None.
</blockquote><h4><a name = "tag_001_014_1021">&nbsp;</a>FUTURE DIRECTIONS</h4><blockquote>
None.
</blockquote><h4><a name = "tag_001_014_1022">&nbsp;</a>SEE ALSO</h4><blockquote>
The <b>XSH</b> specification description of
<i><a href="../xsh/msgrcv.html">msgrcv()</a></i>,
<i><a href="../xsh/msgsnd.html">msgsnd()</a></i>,
<i><a href="../xsh/semget.html">semget()</a></i>,
<i><a href="../xsh/semop.html">semop()</a></i>,
<i><a href="../xsh/shmat.html">shmat()</a></i>,
<i><a href="../xsh/shmdt.html">shmdt()</a></i>,
<i><a href="../xsh/shmget.html">shmget()</a></i>.
</blockquote><hr size=2 noshade>
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Copyright &copy; 1997 The Open Group
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