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mpsleep(9r)
NAME
  mpsleep - General: Blocks the current kernel thread

SYNOPSIS
  int mpsleep(
	  caddr_t channel,
	  long pri,
	  char *wmesg,
	  long timo,
	  void *lockp,
	  long flags );

ARGUMENTS
  channel
      Specifies an address associated with the calling kernel thread to be
      blocked.

  pri Can specify the following values:

      PCATCH  When set, specifies that the sleep request is interruptible.
	      That is, the kernel thread can take asynchronous signals. Not
	      setting the PCATCH flag causes the process to sleep in an
	      uninterruptible state.

      PSUSP   When set, specifies that the process can be asynchronously
	      suspended while waiting.

      On the operating system you cannot use pri to set the scheduling
      priority of the calling process.

  wmesg
      Specifies a mnemonic for the type of wait. The ps command uses this
      mnemonic in its messages about the process.

  timo
      Specifies the maximum amount of time the kernel thread should block.
      The kernel thread blocks a maximum of timo divided by hz seconds. If
      you pass the value 0 (zero), mpsleep assumes there is no timeout.

  lockp
      Specifies a pointer to a lock structure that you want to unlock before
      the process sleeps. If you do not want to release a lock, pass the
      value 0 (zero).

  flags
      Specifies the lock type of the lockp argument and how to handle the
      lock after blocking.

      You can specify one of the following valid lock types, defined in the
      <param.h> file:

      MS_LOCK_SIMPLE
	      Calls mpsleep with a simple lock asserted.

      MS_LOCK_READ
	      Calls mpsleep with a read-only lock asserted on entry.

      MS_LOCK_WRITE
	      Calls mpsleep with a write lock asserted.

      In addition, you can specify one of the following ways to handle the
      lock after blocking:

      MS_LOCK_ON_ERROR
	      Forces mpsleep to relock the lock on failure.

      MS_LOCK_NO_RELOCK
	      Forces mpsleep not to relock after blocking.

DESCRIPTION
  The mpsleep routine blocks (puts to sleep) the current kernel thread until
  a wakeup is issued on the address you specify in the channel argument. This
  routine is the symmetric multiprocessor (SMP) sleep call. The kernel thread
  blocks a maximum of timo divided by hz seconds. The value0 (zero) means
  there is no timeout.

  If you pass the PCATCH flag to the pri argument, the sleep request is
  interruptible, and the kernel thread can take asynchronous signals. If you
  pass the PSUSP flag, the process can be asynchronously suspended while
  waiting.

  The mpsleep routine allows you to specify a pointer to a simple or complex
  lock structure that is associated with some resource.	 If the
  MS_LOCK_NO_RELOCK flag is set, it does not relock the lock after blocking.
  If the MS_LOCK_ON_ERROR flag is set (or no flag is set), mpsleep relocks
  the lock on failure.

NOTES
  This routine is not intended for general use.	 It is mostly used by sleep
  and tsleep and by knowledgeable callers.

  The mpsleep routine cannot be called from within an Interrupt Service
  routine (ISI) because it is illegal to block at interrupt context.

RETURN VALUES
  The mpsleep routine returns the following values:

  0	  Successful completion.

  EINTR	  The sleep has been interrupted by a signal.

  ERESTART
	  The sleep has been interrupted by a signal on a restartable system
	  call.

  EWOULDBLOCK
	  The timeout has expired.

SEE ALSO
  Routines: assert_wait_mesg(9r), clear_wait(9r), thread_block(9r),
  thread_wakeup(9r), thread_wakeup_one(9r)

Index for Section 9r

Alphabetical listing for M

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