


after(n)               Tk Built-In Commands              after(n)


NAME
       after - Execute a command after a time delay

SYNOPSIS
       (after ms)

       (after ms thunk)

       (after 'cancel id)

       (after 'cancel thunk)

       (after 'idle ?thunk?)

       (after info)

       (after info id)


DESCRIPTION
       The  after  procedure  is  used to delay execution of the program or to
       execute a procedure in background after a delay.  It has several forms,
       depending on the first argument to the procedure:

       (after ms)
              Ms must be an integer giving a time in milliseconds.  The proce-
              dure sleeps for ms milliseconds and  then  returns.   While  the
              procedure  is  sleeping  the  application  does not respond to X
              events or any other events.

       (after ms thunk)
              In this form the procedure returns immediately, but it  arranges
              for  a  STk  procedure to be executed ms milliseconds later as a
              background  event  handler.   The  procedure  will  be  executed
              exactly  once, at the given time.  The delayed procedure must be
              a thunk.  If an error occurs while executing the delayed  proce-
              dure  then  the  tkerror  mechanism is used to report the error.
              The after procedure returns a symbol that can be used to  cancel
              the delayed procedure using after cancel.

       (after 'cancel id)
              Cancels the execution of a delayed procedure that was previously
              scheduled.  Id indicates which procedure should be canceled;  it
              must have been the return value from a previous after procedure.
              If the procedure given by id has already been executed then  the
              after cancel procedure has no effect.

       (after 'cancel thunk)
              This  procedure  also  cancels the execution of a delayed proce-
              dure. If there is a pending procedure that matches thunk, it  is
              cancelled  and  will  never be executed; if no such procedure is
              currently pending then the after cancel procedure has no effect.





STk                            3.1                              1





after(n)               Tk Built-In Commands              after(n)


       (after 'idle thunk)
              Arranges  for  the  given thunk to be evaluated later as an idle
              handler The script will be run exactly once, the next  time  the
              Tk  event  loop  is  entered and there are no events to process.
              The procedure returns an identifier that can be used  to  cancel
              the  delayed  procedure  using after cancel.  If an error occurs
              while executing the script then the tkerror mechanism is used to
              report the error.

       (after 'info id)

       (after 'info)
              This  procedure  returns  information  about existing event han-
              dlers.  If no  id  argument  is  supplied,  then  the  procedure
              returns  a  list  of the identifiers for all existing event han-
              dlers created by the after procedure for this  interpreter.   If
              id  is  supplied, it specifies an existing handler; id must have
              been the return value from some previous call to  after  and  it
              must not have triggered yet or been cancelled.  In this case the
              procedure returns a list with two elements.  The  first  element
              of  the  list  is  the script associated with id, and the second
              element is either idle or timer to indicate what kind  of  event
              handler it is.



SEE ALSO
       tkerror





























STk                            3.1                              2


