1IPCS(1P) POSIX Programmer's Manual IPCS(1P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
12 ipcs - report XSI interprocess communication facilities status
13
15 ipcs [-qms][-a | -bcopt]
16
18 The ipcs utility shall write information about active interprocess com‐
19 munication facilities.
20 Without options, information shall be written in short format for mes‐
22 sage queues, shared memory segments, and semaphore sets that are cur‐
23 rently active in the system. Otherwise, the information that is dis‐
24 played is controlled by the options specified.
25
27 The ipcs facility supports the Base Definitions volume of
28 IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
29 The ipcs utility accepts the following options:
31 -q Write information about active message queues.
33 -m Write information about active shared memory segments.
35 -s Write information about active semaphore sets.
37 If -q, -m, or -s are specified, only information about those facilities
40 shall be written. If none of these three are specified, information
41 about all three shall be written subject to the following options:
42 -a Use all print options. (This is a shorthand notation for -b, -c,
44 -o, -p, and -t.)
45 -b Write information on maximum allowable size. (Maximum number of
47 bytes in messages on queue for message queues, size of segments
48 for shared memory, and number of semaphores in each set for sem‐
49 aphores.)
50 -c Write creator's user name and group name; see below.
52 -o Write information on outstanding usage. (Number of messages on
54 queue and total number of bytes in messages on queue for message
55 queues, and number of processes attached to shared memory seg‐
56 ments.)
57 -p Write process number information. (Process ID of the last
59 process to send a message and process ID of the last process to
60 receive a message on message queues, process ID of the creating
61 process, and process ID of the last process to attach or detach
62 on shared memory segments.)
63 -t Write time information. (Time of the last control operation that
65 changed the access permissions for all facilities, time of the
66 last msgsnd() and msgrcv() operations on message queues, time of
67 the last shmat() and shmdt() operations on shared memory, and
68 time of the last semop() operation on semaphores.)
69
72 None.
73
75 Not used.
76
78 * The group database
79 * The user database
81
83 The following environment variables shall affect the execution of ipcs:
84 LANG Provide a default value for the internationalization variables
86 that are unset or null. (See the Base Definitions volume of
87 IEEE Std 1003.1-2001, Section 8.2, Internationalization Vari‐
88 ables for the precedence of internationalization variables used
89 to determine the values of locale categories.)
90 LC_ALL If set to a non-empty string value, override the values of all
92 the other internationalization variables.
93 LC_CTYPE
95 Determine the locale for the interpretation of sequences of
96 bytes of text data as characters (for example, single-byte as
97 opposed to multi-byte characters in arguments).
98 LC_MESSAGES
100 Determine the locale that should be used to affect the format
101 and contents of diagnostic messages written to standard error.
102 NLSPATH
104 Determine the location of message catalogs for the processing of
105 LC_MESSAGES .
106 TZ Determine the timezone for the date and time strings written by
108 ipcs. If TZ is unset or null, an unspecified default timezone
109 shall be used.
110
113 Default.
114
116 An introductory line shall be written with the format:
117 "IPC status from %s as of %s\n", <source>, <date>
120 where <source> indicates the source used to gather the statistics and
122 <date> is the information that would be produced by the date command
123 when invoked in the POSIX locale.
124 The ipcs utility then shall create up to three reports depending upon
126 the -q, -m, and -s options. The first report shall indicate the status
127 of message queues, the second report shall indicate the status of
128 shared memory segments, and the third report shall indicate the status
129 of semaphore sets.
130 If the corresponding facility is not installed or has not been used
132 since the last reboot, then the report shall be written out in the for‐
133 mat:
134 "%s facility not in system.\n", <facility>
137 where <facility> is Message Queue, Shared Memory, or Semaphore, as
139 appropriate. If the facility has been installed and has been used since
140 the last reboot, column headings separated by one or more spaces and
141 followed by a <newline> shall be written as indicated below followed by
142 the facility name written out using the format:
143 "%s:\n", <facility>
146 where <facility> is Message Queues, Shared Memory, or Semaphores, as
148 appropriate. On the second and third reports the column headings need
149 not be written if the last column headings written already provide col‐
150 umn headings for all information in that report.
151 The column headings provided in the first column below and the meaning
153 of the information in those columns shall be given in order below; the
154 letters in parentheses indicate the options that shall cause the corre‐
155 sponding column to appear; "all" means that the column shall always
156 appear. Each column is separated by one or more <space>s. Note that
157 these options only determine what information is provided for each
158 report; they do not determine which reports are written.
159 T (all)
161 Type of facility:
162 q
164 Message queue.
165 m
167 Shared memory segment.
168 s
170 Semaphore.
171 This field is a single character written using the format %c .
174 ID (all)
176 The identifier for the facility entry. This field shall be writ‐
177 ten using the format %d .
178 KEY (all)
180 The key used as an argument to msgget(), semget(), or shmget()
181 to create the facility entry.
182 Note:
184 The key of a shared memory segment is changed to IPC_PRIVATE
185 when the segment has been removed until all processes attached
186 to the segment detach it.
187 This field shall be written using the format 0x%x.
189 MODE (all)
191 The facility access modes and flags. The mode shall consist of
192 11 characters that are interpreted as follows.
193 The first character shall be:
195 S
197 If a process is waiting on a msgsnd() operation.
198 -
200 If the above is not true.
201 The second character shall be:
204 R
206 If a process is waiting on a msgrcv() operation.
207 C or -
209 If the associated shared memory segment is to be cleared when
210 the first attach operation is executed.
211 -
213 If none of the above is true.
214 The next nine characters shall be interpreted as three sets of three
217 bits each. The first set refers to the owner's permissions; the next to
218 permissions of others in the usergroup of the facility entry; and the
219 last to all others. Within each set, the first character indicates per‐
220 mission to read, the second character indicates permission to write or
221 alter the facility entry, and the last character is a minus sign ( '-'
222 ).
223 The permissions shall be indicated as follows:
225 r
227 If read permission is granted.
228 w
230 If write permission is granted.
231 a
233 If alter permission is granted.
234 -
236 If the indicated permission is not granted.
237 The first character following the permissions specifies if there is an
240 alternate or additional access control method associated with the
241 facility. If there is no alternate or additional access control method
242 associated with the facility, a single <space> shall be written; other‐
243 wise, another printable character is written.
244 OWNER (all)
246 The user name of the owner of the facility entry. If the user
247 name of the owner is found in the user database, at least the
248 first eight column positions of the name shall be written using
249 the format %s . Otherwise, the user ID of the owner shall be
250 written using the format %d .
251 GROUP (all)
253 The group name of the owner of the facility entry. If the group
254 name of the owner is found in the group database, at least the
255 first eight column positions of the name shall be written using
256 the format %s . Otherwise, the group ID of the owner shall be
257 written using the format %d .
258 The following nine columns shall be only written out for message
261 queues:
262 CREATOR (a,c)
264 The user name of the creator of the facility entry. If the user
265 name of the creator is found in the user database, at least the
266 first eight column positions of the name shall be written using
267 the format %s . Otherwise, the user ID of the creator shall be
268 written using the format %d .
269 CGROUP (a,c)
271 The group name of the creator of the facility entry. If the
272 group name of the creator is found in the group database, at
273 least the first eight column positions of the name shall be
274 written using the format %s . Otherwise, the group ID of the
275 creator shall be written using the format %d .
276 CBYTES (a,o)
278 The number of bytes in messages currently outstanding on the
279 associated message queue. This field shall be written using the
280 format %d .
281 QNUM (a,o)
283 The number of messages currently outstanding on the associated
284 message queue. This field shall be written using the format %d .
285 QBYTES (a,b)
287 The maximum number of bytes allowed in messages outstanding on
288 the associated message queue. This field shall be written using
289 the format %d .
290 LSPID (a,p)
292 The process ID of the last process to send a message to the
293 associated queue. This field shall be written using the format:
294 "%d", <pid>
297 where <pid> is 0 if no message has been sent to the corresponding mes‐
299 sage queue; otherwise, <pid> shall be the process ID of the last
300 process to send a message to the queue.
301 LRPID (a,p)
303 The process ID of the last process to receive a message from the
304 associated queue. This field shall be written using the format:
305 "%d", <pid>
308 where <pid> is 0 if no message has been received from the corresponding
310 message queue; otherwise, <pid> shall be the process ID of the last
311 process to receive a message from the queue.
312 STIME (a,t)
314 The time the last message was sent to the associated queue. If a
315 message has been sent to the corresponding message queue, the
316 hour, minute, and second of the last time a message was sent to
317 the queue shall be written using the format %d : %2.2d : %2.2d .
318 Otherwise, the format " no-entry" shall be written.
319 RTIME (a,t)
321 The time the last message was received from the associated
322 queue. If a message has been received from the corresponding
323 message queue, the hour, minute, and second of the last time a
324 message was received from the queue shall be written using the
325 format %d : %2.2d : %2.2d . Otherwise, the format " no-entry"
326 shall be written.
327 The following eight columns shall be only written out for shared memory
330 segments.
331 CREATOR (a,c)
333 The user of the creator of the facility entry. If the user name
334 of the creator is found in the user database, at least the first
335 eight column positions of the name shall be written using the
336 format %s . Otherwise, the user ID of the creator shall be writ‐
337 ten using the format %d .
338 CGROUP (a,c)
340 The group name of the creator of the facility entry. If the
341 group name of the creator is found in the group database, at
342 least the first eight column positions of the name shall be
343 written using the format %s . Otherwise, the group ID of the
344 creator shall be written using the format %d .
345 NATTCH (a,o)
347 The number of processes attached to the associated shared memory
348 segment. This field shall be written using the format %d .
349 SEGSZ (a,b)
351 The size of the associated shared memory segment. This field
352 shall be written using the format %d .
353 CPID (a,p)
355 The process ID of the creator of the shared memory entry. This
356 field shall be written using the format %d .
357 LPID (a,p)
359 The process ID of the last process to attach or detach the
360 shared memory segment. This field shall be written using the
361 format:
362 "%d", <pid>
365 where <pid> is 0 if no process has attached the corresponding shared
367 memory segment; otherwise, <pid> shall be the process ID of the last
368 process to attach or detach the segment.
369 ATIME (a,t)
371 The time the last attach on the associated shared memory segment
372 was completed. If the corresponding shared memory segment has
373 ever been attached, the hour, minute, and second of the last
374 time the segment was attached shall be written using the format
375 %d : %2.2d : %2.2d . Otherwise, the format " no-entry" shall be
376 written.
377 DTIME (a,t)
379 The time the last detach on the associated shared memory segment
380 was completed. If the corresponding shared memory segment has
381 ever been detached, the hour, minute, and second of the last
382 time the segment was detached shall be written using the format
383 %d : %2.2d : %2.2d . Otherwise, the format " no-entry" shall be
384 written.
385 The following four columns shall be only written out for semaphore
388 sets:
389 CREATOR (a,c)
391 The user of the creator of the facility entry. If the user name
392 of the creator is found in the user database, at least the first
393 eight column positions of the name shall be written using the
394 format %s . Otherwise, the user ID of the creator shall be writ‐
395 ten using the format %d .
396 CGROUP (a,c)
398 The group name of the creator of the facility entry. If the
399 group name of the creator is found in the group database, at
400 least the first eight column positions of the name shall be
401 written using the format %s . Otherwise, the group ID of the
402 creator shall be written using the format %d .
403 NSEMS (a,b)
405 The number of semaphores in the set associated with the sema‐
406 phore entry. This field shall be written using the format %d .
407 OTIME (a,t)
409 The time the last semaphore operation on the set associated with
410 the semaphore entry was completed. If a semaphore operation has
411 ever been performed on the corresponding semaphore set, the
412 hour, minute, and second of the last semaphore operation on the
413 semaphore set shall be written using the format %d : %2.2d :
414 %2.2d . Otherwise, the format " no-entry" shall be written.
415 The following column shall be written for all three reports when it is
418 requested:
419 CTIME (a,t)
421 The time the associated entry was created or changed. The hour,
422 minute, and second of the time when the associated entry was
423 created shall be written using the format %d : %2.2d : %2.2d .
424
427 The standard error shall be used only for diagnostic messages.
428
430 None.
431
433 None.
434
436 The following exit values shall be returned:
437 0 Successful completion.
439 >0 An error occurred.
441
444 Default.
445 The following sections are informative.
447
449 Things can change while ipcs is running; the information it gives is
450 guaranteed to be accurate only when it was retrieved.
451
453 None.
454
456 None.
457
459 None.
460
462 The System Interfaces volume of IEEE Std 1003.1-2001, msgrcv(),
463 msgsnd(), semget(), semop(), shmat(), shmdt(), shmget()
464
466 Portions of this text are reprinted and reproduced in electronic form
467 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
468 -- Portable Operating System Interface (POSIX), The Open Group Base
469 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
470 Electrical and Electronics Engineers, Inc and The Open Group. In the
471 event of any discrepancy between this version and the original IEEE and
472 The Open Group Standard, the original IEEE and The Open Group Standard
473 is the referee document. The original Standard can be obtained online
474 at http://www.opengroup.org/unix/online.html .
475IEEE/The Open Group 2003 IPCS(1P)