select_wakeup(9r) [osf1 man page]

select_wakeup(9r)														 select_wakeup(9r)

NAME

       select_wakeup - General: Wakes up a kernel thread

SYNOPSIS

       void select_wakeup(
	       sel_queue_t *selq );

ARGUMENTS

       Specifies a pointer to a sel_queue structure.

DESCRIPTION

       The  select_wakeup  routine  wakes  up  a  kernel thread that is suspended while waiting for an event on the specified device. A user-level
       process can use the select system call to cause the process to be suspended while waiting for an event to happen on a device. For  example,
       a  graphics  application  may issue a select call while waiting for mouse or keyboard input to arrive. In this case the process would issue
       the select system call, which would indirectly call the graphics driver's select routine (through the driver's select entry  point  in  the
       dsent  table)  to  determine if any input is available. If input is available, the select call may return immediately.  If no input is cur-
       rently available, the graphics driver would suspend the process until input arrived.

       For this example, when the graphics driver has received input (typically through its interrupt handler), it causes any processes  suspended
       from  calling  select  to continue by calling the select_wakeup routine.  This causes any process currently suspended on the select channel
       (as specified by the selq argument) to resume.

RETURN VALUES

       None

SEE ALSO

       Routines: select_dequeue(9r), select_dequeue_all(9r), select_enqueue(9r)

       System Calls: select(2)

																 select_wakeup(9r)

wakeup(9r)																wakeup(9r)

NAME

       wakeup - General: Wakes up all processes sleeping on a specified address

SYNOPSIS

       void wakeup(
	       caddr_t channel );

ARGUMENTS

       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 request-
       ing 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)

																	wakeup(9r)