NAME

ipcrm − remove a message queue, semaphore set, or shared memory ID

SYNOPSIS

ipcrm [ options ]

DESCRIPTION

ipcrm removes one or more messages, semaphores, or shared memory identifiers.  The identifiers are specified by the following options:

−q msqid Remove the message queue identifier msqid from the system and destroy the message queue and data structure associated with it. 

−m shmid Remove the shared memory identifier shmid from the system.  The shared memory segment and data structure associated with it are destroyed after the last detach. 

−s semid Remove the semaphore identifier semid from the system and destroy the set of semaphores and data structure associated with it. 

−Q msgkey Remove the message queue identifier, created with key msgkey, from the system and destroy the message queue and data structure associated with it. 

−M shmkey Removes the shared memory identifier, created with key shmkey, from the system.  The shared memory segment and data structure associated with it are destroyed after the last detach. 

−S semkey Remove the semaphore identifier, created with key semkey, from the system and destroy the set of semaphores and data structure associated with it. 

The details of the removes are described in msgctl(2), shmctl(2), and semctl(2).  Use the ipcs command to find the identifiers and keys. 

SECURITY FEATURES

The following security features are in effect when the system is running CX/SX configured to B1 security. 

Because ipcrm uses IPC system calls, it does not require access to kernel address space (via /dev/kmem, see mem(7)) and does not need to belong to the Trusted Computing Base (TCB).  The standard command allows the creator or owner of an IPC object to remove that object without regard to the security implications of the removal of the object.  The secured ipcrm(1) command allows the creator or owner to remove the object only if the subject’s current security level is equal to that of the object.  See intro(2SX) for a definition of “security label”. 

The superuser can remove all IPC objects.  There is no functional difference between the standard and the secured ipcrm(1) as far as the superuser is concerned. 

SEE ALSO

ipcs(1), shmdefine(1). 
msgctl(2), msgget(2), msgop(2), semctl(2), semget(2), semop(2), shmctl(2), shmget(2), shmop(2) in the CX/UX Programmer’s Reference Manual. 

CX/UX User’s Reference Manual