Index for Section 9r

Alphabetical listing for W

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wakeup(9r)
NAME
  wakeup - General: Wakes up all processes sleeping on a specified address

SYNOPSIS
  void wakeup(
	  caddr_t channel );

ARGUMENTS
  channel
      Specifies the address on which the wakeup is to be issued.

DESCRIPTION
  The wakeup routine wakes up all processes sleeping on the address specified
  by the channel argument. All processes sleeping on this address are
  awakened and made ready to be scheduled according to the priorities they
  specified when they went to sleep. It is possible that there are no
  processes sleeping on the channel at the time the wakeup is issued. This
  situation can occur for a variety of reasons and does not represent an
  error condition.

  The sleep and wakeup routines block and unblock a process. Generally, a
  device driver issues these routines on behalf of a process requesting I/O
  while a transfer is in progress. That is, a process requesting I/O is put
  to sleep on an address associated with the request by the appropriate
  device driver routine. When the transfer has asynchronously completed, the
  device driver interrupt service routine issues a wakeup on the address
  associated with the completed request. This action makes the relevant
  process to be scheduled.

  The process resumes execution within the relevant device driver routine at
  the point immediately following the request to sleep. The driver, on behalf
  of the process, can then determine whether the condition for which it was
  sleeping (in this example, completion of an I/O request) has been removed.
  If so, it can continue on to complete the I/O request. Otherwise, the
  appropriate driver routine can decide to put the process back to sleep to
  await removal of the indicated condition.

RETURN VALUES
  None

SEE ALSO
  Routines: mpsleep(9r), sleep(9r)

Index for Section 9r

Alphabetical listing for W

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