PROLOG | NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPERANDS | STDIN | INPUT FILES | ENVIRONMENT VARIABLES | ASYNCHRONOUS EVENTS | STDOUT | STDERR | OUTPUT FILES | EXTENDED DESCRIPTION | EXIT STATUS | CONSEQUENCES OF ERRORS | APPLICATION USAGE | EXAMPLES | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

IPCS(1P)                  POSIX Programmer's Manual                 IPCS(1P)

PROLOG         top

       This manual page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior), or
       the interface may not be implemented on Linux.

NAME         top

       ipcs — report XSI interprocess communication facilities status

SYNOPSIS         top

       ipcs [−qms] [−a|−bcopt]

DESCRIPTION         top

       The ipcs utility shall write information about active interprocess
       communication facilities.

       Without options, information shall be written in short format for
       message queues, shared memory segments, and semaphore sets that are
       currently active in the system. Otherwise, the information that is
       displayed is controlled by the options specified.

OPTIONS         top

       The ipcs utility shall conform to the Base Definitions volume of
       POSIX.1‐2008, Section 12.2, Utility Syntax Guidelines.

       The ipcs utility accepts the following options:

       −q        Write information about active message queues.

       −m        Write information about active shared memory segments.

       −s        Write information about active semaphore sets.

       If −q, −m, or −s are specified, only information about those
       facilities shall be written. If none of these three are specified,
       information about all three shall be written subject to the following
       options:

       −a        Use all print options. (This is a shorthand notation for
                 −b, −c, −o, −p, and −t.)

       −b        Write information on maximum allowable size. (Maximum
                 number of bytes in messages on queue for message queues,
                 size of segments for shared memory, and number of
                 semaphores in each set for semaphores.)

       −c        Write creator's user name and group name; see below.

       −o        Write information on outstanding usage. (Number of messages
                 on queue and total number of bytes in messages on queue for
                 message queues, and number of processes attached to shared
                 memory segments.)

       −p        Write process number information. (Process ID of the last
                 process to send a message and process ID of the last
                 process to receive a message on message queues, process ID
                 of the creating process, and process ID of the last process
                 to attach or detach on shared memory segments.)

       −t        Write time information. (Time of the last control operation
                 that changed the access permissions for all facilities,
                 time of the last msgsnd() and msgrcv() operations on
                 message queues, time of the last shmat() and shmdt()
                 operations on shared memory, and time of the last semop()
                 operation on semaphores.)

OPERANDS         top

       None.

STDIN         top

       Not used.

INPUT FILES         top

        *  The group database

        *  The user database

ENVIRONMENT VARIABLES         top

       The following environment variables shall affect the execution of
       ipcs:

       LANG      Provide a default value for the internationalization
                 variables that are unset or null. (See the Base Definitions
                 volume of POSIX.1‐2008, Section 8.2, Internationalization
                 Variables for the precedence of internationalization
                 variables used to determine the values of locale
                 categories.)

       LC_ALL    If set to a non-empty string value, override the values of
                 all the other internationalization variables.

       LC_CTYPE  Determine the locale for the interpretation of sequences of
                 bytes of text data as characters (for example, single-byte
                 as opposed to multi-byte characters in arguments).

       LC_MESSAGES
                 Determine the locale that should be used to affect the
                 format and contents of diagnostic messages written to
                 standard error.

       NLSPATH   Determine the location of message catalogs for the
                 processing of LC_MESSAGES.

       TZ        Determine the timezone for the date and time strings
                 written by ipcs.  If TZ is unset or null, an unspecified
                 default timezone shall be used.

ASYNCHRONOUS EVENTS         top

       Default.

STDOUT         top

       An introductory line shall be written with the format:

           "IPC status from %s as of %s\n", <source>, <date>

       where <source> indicates the source used to gather the statistics and
       <date> is the information that would be produced by the date command
       when invoked in the POSIX locale.

       The ipcs utility then shall create up to three reports depending upon
       the −q, −m, and −s options. The first report shall indicate the
       status of message queues, the second report shall indicate the status
       of shared memory segments, and the third report shall indicate the
       status of semaphore sets.

       If the corresponding facility is not installed or has not been used
       since the last reboot, then the report shall be written out in the
       format:

           "%s facility not in system.\n", <facility>

       where <facility> is Message Queue, Shared Memory, or Semaphore, as
       appropriate. If the facility has been installed and has been used
       since the last reboot, column headings separated by one or more
       <space> characters and followed by a <newline> shall be written as
       indicated below followed by the facility name written out using the
       format:

           "%s:\n", <facility>

       where <facility> is Message Queues, Shared Memory, or Semaphores, as
       appropriate. On the second and third reports the column headings need
       not be written if the last column headings written already provide
       column headings for all information in that report.

       The column headings provided in the first column below and the
       meaning of the information in those columns shall be given in order
       below; the letters in parentheses indicate the options that shall
       cause the corresponding column to appear; ``all'' means that the
       column shall always appear. Each column is separated by one or more
       <space> characters. Note that these options only determine what
       information is provided for each report; they do not determine which
       reports are written.

       T (all)     Type of facility:

                   q       Message queue.

                   m       Shared memory segment.

                   s       Semaphore.

                   This field is a single character written using the format
                   %c.

       ID (all)    The identifier for the facility entry. This field shall
                   be written using the format %d.

       KEY (all)   The key used as an argument to msgget(), semget(), or
                   shmget() to create the facility entry.

                   Note:     The key of a shared memory segment is changed
                             to IPC_PRIVATE when the segment has been
                             removed until all processes attached to the
                             segment detach it.

                   This field shall be written using the format 0x%x.

       MODE (all)  The facility access modes and flags. The mode shall
                   consist of 11 characters that are interpreted as follows.

                   The first character shall be:

                   S       If a process is waiting on a msgsnd() operation.

                   −       If the above is not true.

                   The second character shall be:

                   R       If a process is waiting on a msgrcv() operation.

                   C or −  If the associated shared memory segment is to be
                           cleared when the first attach operation is
                           executed.

                   −       If none of the above is true.

                   The next nine characters shall be 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 ('−').

                   The permissions shall be indicated as follows:

                   r       If read permission is granted.

                   w       If write permission is granted.

                   a       If alter permission is granted.

                   −       If the indicated permission is not granted.

                   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> shall be written;
                   otherwise, another printable character is written.

       OWNER (all) 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 shall
                   be written using the format %s.  Otherwise, the user ID
                   of the owner shall be written using the format %d.

       GROUP (all) 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
                   shall be written using the format %s.  Otherwise, the
                   group ID of the owner shall be written using the format
                   %d.

       The following nine columns shall be only written out for message
       queues:

       CREATOR (a,c)
                   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 shall be written using the format %s.
                   Otherwise, the user ID of the creator shall be written
                   using the format %d.

       CGROUP (a,c)
                   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 shall be written using the format %s.
                   Otherwise, the group ID of the creator shall be written
                   using the format %d.

       CBYTES (a,o)
                   The number of bytes in messages currently outstanding on
                   the associated message queue. This field shall be written
                   using the format %d.

       QNUM (a,o)  The number of messages currently outstanding on the
                   associated message queue. This field shall be written
                   using the format %d.

       QBYTES (a,b)
                   The maximum number of bytes allowed in messages
                   outstanding on the associated message queue. This field
                   shall be written using the format %d.

       LSPID (a,p) The process ID of the last process to send a message to
                   the associated queue. This field shall be written using
                   the format:

                       "%d", <pid>

                   where <pid> is 0 if no message has been sent to the
                   corresponding message queue; otherwise, <pid> shall be
                   the process ID of the last process to send a message to
                   the queue.

       LRPID (a,p) The process ID of the last process to receive a message
                   from the associated queue. This field shall be written
                   using the format:

                       "%d", <pid>

                   where <pid> is 0 if no message has been received from the
                   corresponding message queue; otherwise, <pid> shall be
                   the process ID of the last process to receive a message
                   from the queue.

       STIME (a,t) 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 shall be written
                   using the format %d:%2.2d:%2.2d.  Otherwise, the format
                   " no-entry" shall be written.

       RTIME (a,t) 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 shall be written using the format %d:%2.2d:%2.2d.
                   Otherwise, the format " no-entry" shall be written.

       The following eight columns shall be only written out for shared
       memory segments.

       CREATOR (a,c)
                   The user 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
                   shall be written using the format %s.  Otherwise, the
                   user ID of the creator shall be written using the format
                   %d.

       CGROUP (a,c)
                   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 shall be written using the format %s.
                   Otherwise, the group ID of the creator shall be written
                   using the format %d.

       NATTCH (a,o)
                   The number of processes attached to the associated shared
                   memory segment. This field shall be written using the
                   format %d.

       SEGSZ (a,b) The size of the associated shared memory segment. This
                   field shall be written using the format %d.

       CPID (a,p)  The process ID of the creator of the shared memory entry.
                   This field shall be written using the format %d.

       LPID (a,p)  The process ID of the last process to attach or detach
                   the shared memory segment. This field shall be written
                   using the format:

                       "%d", <pid>

                   where <pid> is 0 if no process has attached the
                   corresponding shared memory segment; otherwise, <pid>
                   shall be the process ID of the last process to attach or
                   detach the segment.

       ATIME (a,t) 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 shall be
                   written using the format %d:%2.2d:%2.2d.  Otherwise, the
                   format " no-entry" shall be written.

       DTIME (a,t) 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 shall be
                   written using the format %d:%2.2d:%2.2d.  Otherwise, the
                   format " no-entry" shall be written.

       The following four columns shall be only written out for semaphore
       sets:

       CREATOR (a,c)
                   The user 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
                   shall be written using the format %s.  Otherwise, the
                   user ID of the creator shall be written using the format
                   %d.

       CGROUP     (a,c)
                   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 shall be written using the format %s.
                   Otherwise, the group ID of the creator shall be written
                   using the format %d.

       NSEMS (a,b) The number of semaphores in the set associated with the
                   semaphore entry. This field shall be written using the
                   format %d.

       OTIME (a,t) 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
                   shall be written using the format %d:%2.2d:%2.2d.
                   Otherwise, the format " no-entry" shall be written.

       The following column shall be written for all three reports when it
       is requested:

       CTIME (a,t) The time the associated entry was created or changed. The
                   hour, minute, and second of the time when the associated
                   entry was created shall be written using the format
                   %d:%2.2d:%2.2d.

STDERR         top

       The standard error shall be used only for diagnostic messages.

OUTPUT FILES         top

       None.

EXTENDED DESCRIPTION         top

       None.

EXIT STATUS         top

       The following exit values shall be returned:

        0    Successful completion.

       >0    An error occurred.

CONSEQUENCES OF ERRORS         top

       Default.

       The following sections are informative.

APPLICATION USAGE         top

       Things can change while ipcs is running; the information it gives is
       guaranteed to be accurate only when it was retrieved.

EXAMPLES         top

       None.

RATIONALE         top

       None.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       ipcrm(1p)

       The Base Definitions volume of POSIX.1‐2008, Chapter 8, Environment
       Variables, Section 12.2, Utility Syntax Guidelines

       The System Interfaces volume of POSIX.1‐2008, msgrcv(3p), msgsnd(3p),
       semget(3p), semop(3p), shmat(3p), shmdt(3p), shmget(3p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The Open
       Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
       applied.) In the event of any discrepancy between this version and
       the original IEEE and The Open Group Standard, the original IEEE and
       The Open Group Standard is the referee document. The original
       Standard can be obtained online at http://www.unix.org/online.html .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the
       source files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                 2013                            IPCS(1P)

Pages that refer to this page: ipcrm(1p)