qtimeout(9F)

NAME

qtimeout − execute a function after a specified length of time

SYNOPSIS

#include <sys/stream.h>
#include <sys/ddi.h>

int qtimeout( queue_t ∗q, void (∗ftn)(), caddr_t arg, long ticks );

INTERFACE LEVEL

Solaris DDI specific (Solaris DDI).

ARGUMENTS

q Pointer to STREAMS queue structure.

ftn 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.

DESCRIPTION

The qtimeout() function schedules the specified function ftn to be called after a specified time interval. ftn 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) man page. ) 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

Under normal conditions, an integer timeout identifier is returned.

The qtimeout() function returns an identifier that may be passed to the quntimeout(9F) function to cancel a pending request. Note: No value is returned from the called function.

CONTEXT

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

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