execute a function on a specified processor after a specified length of time
Synopsis (Not in current DDI version)
toid_t dtimeout(void (*fn)(), void *arg, long ticks, pl_t pl,
dtimeout causes the function specified by fn to be
called after the time interval specified by ticks,
on the processor specified by processor,
at the interrupt priority level specified by pl.
arg will be passed as the only argument to function fn.
The dtimeout call returns immediately
without waiting for the specified function to execute.
Function to execute on the specified processor
when the time increment expires.
The function specified by fn runs in interrupt
context in HDK Technical Reference
and must not lower the interrupt priority
below that specified by the pl argument."
fn will be run at some point
after the time interval expires.
Like a device interrupt (see
it may need to be deferred
until the interrupt priority is dropped
to a sufficiently low level.
Timer callback functions are only run
when the interrupt priority level is plbase;
they never interrupt device interrupt handlers.
Argument to the function.
Number of clock ticks to wait before the function is called.
The length of time before the function is called
is not guaranteed to be exactly equal to the requested time,
but will be at least ticks-1 clock ticks in length.
A ticks argument of 0 has the same effect
as a ticks argument of 1.
Both will result in an approximate wait of between 0 and 1 tick
The flag TO_PERIODIC can be
logically OR'ed into the ticks argument
to indicate a repeating periodic timer.
When this is used, the specified function will be called
every ticks clock ticks, instead of just once;
successive calls will compensate for any delay in a previous
cycle, so that there is no cumulative drift.
The repeating timer can be canceled by
just like any other timeout.
The interrupt priority level at which the function will be called.
pl must specify a priority level
greater than or equal to pltimeout,
so plbase cannot be used.
for a list of values for pl.
Processor on which the function must execute.
If the function specified by fn is successfully scheduled,
returns a non-zero identifier
that can be passed to
to cancel the request.
If the function could not be scheduled on the specified processor,
returns a value of 0.
This directed timeout capability provides
a form of dynamic processor binding for driver code.
Drivers should be careful to cancel any pending
functions that access data structures
before these structures are de-initialized or deallocated.
Context and synchronization
Non-blockable, interrupt, user, or blockable
3, 5, 5mp, 6, 6mp, 7, 7mp, 7.1, 7.1mp
Differences between versions
is not supported in DDI 8.
``Timeouts'' in HDK Technical Reference
19 June 2005
© 2005 The SCO Group, Inc. All rights reserved.
OpenServer 6 and UnixWare (SVR5) HDK - June 2005