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Kernel Functions for Driversqtimeout(9F)


NAME

 qtimeout - execute a function after a specified length of time

SYNOPSIS

 
#include <sys/stream.h> 
#include <sys/ddi.h>
timeout_id_t qtimeout(queue_t *q, void (*func)(void *), void *arg, clock_t ticks);

INTERFACE LEVEL

 

Solaris DDI specific (Solaris DDI).

PARAMETERS

 
q
Pointer to STREAMS queue structure.
func
Kernel function to invoke when the time increment expires.
arg
Argument to the function.
ticks
Number of clock ticks to wait before the function is called. Use drv_usectohz(9F) to convert microseconds to clock ticks.

DESCRIPTION

 

The qtimeout() function schedules the specified function func to be called after a specified time interval. func is called with arg as a parameter. Control is immediately returned to the caller. This is useful when an event is known to occur within a specific time frame, or when you want to wait for I/O processes when an interrupt is not available or might cause problems. The exact time interval over which the timeout takes effect cannot be guaranteed, but the value given is a close approximation.

The qtimeout() function is tailored to be used with the enhanced STREAMS framework interface which is based on the concept of perimeters. (See mt-streams(9F).) qtimeout() schedules the specified function to execute after entering the perimeters associated with the queue passed in as the first parameter to qtimeout(). All outstanding timeouts should be cancelled before a driver closes or module returns.

qprocson(9F) must be called before calling qtimeout().

RETURN VALUES

 

qtimeout() returns an opaque non-zero timeout identifier that can be passed to quntimeout(9F) to cancel the request. Note: No value is returned from the called function.

CONTEXT

 

qtimeout() can be called from user or interrupt context.

SEE ALSO

 

drv_usectohz(9F), mt-streams(9F), qbufcall(9F), qprocson(9F), qunbufcall(9F), quntimeout(9F)

Writing Device Drivers

STREAMS Programming Guide


SunOS 5.9Go To TopLast Changed 11 Nov 1996

 
      
      
Copyright 2002 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.