Kernel Functions for Drivers                         qtimeout(9F)



NAME
     qtimeout - execute a function after a  specified  length  of
     time

SYNOPSIS
     #include 
     #include 


     timeoutidt qtimeout(queuet *q, void (*func)(void *),
          void *arg, clockt ticks);


INTERFACE LEVEL
     Solaris DI specific (Solaris DI).

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   drvusectohz(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



SunOS 5.11          Last change: 16 Jan 2006                    1






Kernel Functions for Drivers                         qtimeout(9F)



     routine can  block  and  before  the  close   routine  calls
     qprocsoff(9F).


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

RETURN VALUES
     The qtimeout() function 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
     The qtimeout() function can be called from user,  interrupt,
     or kernel context.

SEE ALSO
     drvusectohz(9F),       mt-streams(9F),        qbufcall(9F),
     qprocson(9F), qunbufcall(9F), quntimeout(9F)


     Writing Device Drivers


     STREAMS Programming Guide





























SunOS 5.11          Last change: 16 Jan 2006                    2