[Bug 62858] Re: shmctl man differs from kernel operation

[Launchpad Bug Tracker]

[Expired for manpages (Ubuntu) because there has been no activity for 60
days.]

** Changed in: manpages (Ubuntu)
       Status: Incomplete => Expired

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https://bugs.launchpad.net/bugs/62858

Title:
  shmctl man differs from kernel operation

Status in manpages package in Ubuntu:
  Expired

Bug description:
  shmget() allows creation of shared memory segments with key_t key
  values that can be used by other processes to identify them.
  Traditionally, under Linux the shmctl() call could be used to caused a
  shared memory segment to destroy itself upon the last detachment by
  IPC_RMID, and this would have no other impact on the operation of the
  shared memory segment. This behavior of IPC_RMID is documented (in the
  shmctl man page) and is quite useful.  However, setting IPC_RMID in
  recent Linux kernels has the important side effect of CHANGING the key
  associated with the segment to 0 (aka, IPC_PRIVATE).  Ideally, this
  side effect should be removed from the kernel, but the kernel folks
  seem unlikely to do this (the new behavior was mentioned in a
  discussion).  Thus, I suggest fixing the shmctl man page to mention
  this strange behavior in the discussion of IPC_RMID: after "IPC_STAT
  will be set." add the phrase "The segment key may be changed to
  IPC_PRIVATE as a side effect of IPC_RMID."

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