ipcrm

IPCRM(8)                   Linux Programmer's Manual                  IPCRM(8)



NAME
       ipcrm - remove a message queue, semaphore set or shared memory id

SYNOPSIS
       ipcrm [ -M key | -m id | -Q key | -q id | -S key | -s id ] ...

       deprecated usage

       ipcrm [ shm | msg | sem ] id ...

DESCRIPTION
       ipcrm  removes  System  V  interprocess communication (IPC) objects and
       associated data structures from the system.  In order  to  delete  such
       objects,  you must be superuser, or the creator or owner of the object.

       System V IPC objects are of three types: shared memory, message queues,
       and  semaphores.   Deletion  of  a message queue or semaphore object is
       immediate (regardless of whether any process still holds an IPC identi-
       fier for the object).  A shared memory object is only removed after all
       currently attached processes have detached (shmdt(2)) the  object  from
       their virtual address space.

       Two syntax styles are supported.  The old Linux historical syntax spec-
       ifies a three letter keyword indicating which class of object is to  be
       deleted,  followed  by  one or more IPC identifiers for objects of this
       type.

       The SUS-compliant syntax allows  the  specification  of  zero  or  more
       objects of all three types in a single command line, with objects spec-
       ified either by key or by identifier. (See below.)  Both keys and iden-
       tifiers  may  be  specified  in decimal, hexadecimal (specified with an
       initial '0x' or '0X'), or octal (specified with an initial '0').


OPTIONS
       -M shmkey
              removes the shared memory segment created with shmkey after  the
              last detach is performed.

       -m shmid
              removes  the shared memory segment identified by shmid after the
              last detach is performed.

       -Q msgkey
              removes the message queue created with msgkey.

       -q msgid
              removes the message queue identified by msgid.

       -S semkey
              removes the semaphore created with semkey.

       -s semid
              removes the semaphore identified by semid.

       The details of the removes are described in msgctl(2),  shmctl(2),  and
       semctl(2).  The identifiers and keys may be found by using ipcs(8).

NOTES
       In  its  first  Linux  implementation, ipcrm used the deprecated syntax
       shown in the SYNOPSIS.  Functionality present in other *nix implementa-
       tions  of  ipcrm  has  since  been  added, namely the ability to delete
       resources by key (not just identifier), and to respect  the  same  com-
       mand-line  syntax.  For  backward  compatibility the previous syntax is
       still supported.

SEE ALSO
       ipcs(8),  msgctl(2),  msgget(2),   semctl(2),   semget(2),   shmctl(2),
       shmdt(2), shmget(2), ftok(3)



ipcrm                     last change: 19 March 2002                  IPCRM(8)