_________________________________________________________________



NAME

     Tcm_CreateAtHandler, Tcm_DeleteAtHandler

       - C level access to "at" events.


SYNOPSIS

     #include "tcm.h"

     int
     Tcm_CreateAtHandler (startTime, endTime,
                          firePg, fireProc, fireClientData, fireFreeProc,
                          missedPg, missedProc, missedClientData, missFreeProc)
     int
     Tcm_DeleteAtHandler (token)


ARGUMENTS

     startTime      double                (in)      Start of time
                                                    window    (in
                                                    system time).

     endTime        double                (in)      End  of  time
                                                    window    (in
                                                    system time).

     char           *firePg               (in)      Name       of
                                                    priority
                                                    group     for
                                                    fireProc.

     Tk_TimerProc   *fireProc             (in)      Callback   if
                                                    time   window
                                                    hit.

     ClientData     *fireClientData       (in)      ClientData
                                                    for fireProc.

     void           (*fireFreeProc)()     (in)      Procedure  to
                                                    call  to free
                                                    fireClient-
                                                    Data.

     char           *missedPg             (in)      Name       of
                                                    priority
                                                    group     for
                                                    missedProc.

     Tk_IdleProc    *missedProc           (in)      Callback   if
                                                    time   window
                                                    missed.

     ClientData     *missedClientData     (in)      ClientData
                                                    for
                                                    missedProc.

     void           (*missedFreeProc)()   (in)      Procedure  to
                                                    call  to free
                                                    missedClient-
                                                    Data.

     int            token                 (in)      Represents  a
                                                    future   "at"
                                                    event.

_________________________________________________________________



DESCRIPTION

     Users of this function request a C callback  to  be  invoked
     "at" a certain time (hence, the name of this function).  The
     procedure Tcm_CreateAtHandler arranges for  fireProc  to  be
     called within a given time window specified by startTime and
     endTime. If fireProc could not be called  within  the  given
     time window, eventually missedProc is called.  Each callback
     is supplied its respective clientData, and  a  procedure  to
     free  that clientData when it's finished.  Each callback may
     be   NULL,   as   may   the   freeProcs.    The    procedure
     Tcm_CreateAtHandler  returns  a  token  to represent the new
     "at"  event.   The  "at"  event   may   be   deleted   using
     Tcm_DeleteAtHandler.



AUTHOR

     Brian Smith (bsmith@cs.berkeley.edu)
     Steve Yen (syen@cs.berkeley.edu)