qtimeout(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 and
     bufcalls   must   be   cancelled    (using,    respectively,
     quntimeout(9F)  and  qunbufcall(9F))  before  a driver close
     routine can  block  and  before  the  close   routine  calls
     qprocsoff(9F).

     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