wakeup(9r) [osf1 man page]

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)

sleep(9r)																 sleep(9r)

NAME

       sleep - General: Puts a calling process to sleep

SYNOPSIS

       void sleep(
	       caddr_t *channel,
	       long pri );

ARGUMENTS

       Specifies a unique address associated with the calling kernel thread to be put to sleep.  Specifies whether the sleep request is interrupt-
       ible. Setting this argument to the PCATCH flag causes the process to sleep in an interruptible state (that is, the kernel thread  can  take
       asynchronous signals). Not setting the PCATCH flag causes the process to sleep in an uninterruptible state (that is, the kernel thread can-
       not take asynchronous signals).

DESCRIPTION

       The sleep routine puts a calling process to sleep on the address specified by the channel argument. Some common	addresses  are	the  lbolt
       argument, a buf structure, and a proc structure.  This address should be unique to prevent unexpected wake/sleep cycles, which can occur if
       different processes are sleeping on the same address accidentally.  If you set the PCATCH flag in the pri argument, the sleep routine  puts
       signals on the queue and does not wake up the sleeping process.

       The  sleep  and wakeup routines block and then wake up a process. Generally, device drivers call these routines to wait for the transfer to
       complete an interrupt from the device. That is, the write routine of the device driver sleeps on the address of a known location,  and  the
       device's Interrupt Service Interface (ISI) wakes the process when the device interrupts. It is the responsibility of the wakened process to
       check if the condition for which it was sleeping has been removed.

NOTES

       The operating system provides two ways to put a process to sleep: interruptible and uninterruptible. The sleep routine performs an uninter-
       ruptible  sleep	operation  if  you do not set the PCATCH flag and an interruptible sleep operation if you set the PCATCH flag.	This means
       that device drivers cannot call sleep at interrupt context because at interrupt context there is no calling process to  be  put	to  sleep.
       Thus, a device driver's Interrupt Service Interface (ISI) and those routines called from within the ISI must not call the sleep routine.

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

RETURN VALUES

       None

FILES

SEE ALSO

       Routines: wakeup(9r)

																	 sleep(9r)