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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)