


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


NAME
       after - Execute a command after a time delay

SYNOPSIS
       after ms

       after ms ?script script script ...?

       after cancel id

       after cancel script script script ...

       after idle ?script script script ...?

       after info ?id?


DESCRIPTION
       This  command is used to delay execution of the program or
       to execute a command in background after a delay.  It  has
       several forms, depending on the first argument to the com-
       mand:

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

       after ms ?script script script ...?
              In this form the command returns  immediately,  but
              it  arranges  for  a  Tcl command to be executed ms
              milliseconds later as a background  event  handler.
              The  command  will be executed exactly once, at the
              given time.  The delayed command is formed by  con-
              catenating  all  the  script  arguments in the same
              fashion as the concat command.  The command will be
              executed  at  global  level (outside the context of
              any Tcl procedure).  If an error occurs while  exe-
              cuting  the delayed command then the tkerror mecha-
              nism is used to report the error.  The  after  com-
              mand returns an identifier that can be used to can-
              cel the delayed command using after cancel.

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





Tk                             4.1                              1





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


       after cancel script script ...
              This  command  also  cancels  the  execution  of  a
              delayed command.  The script arguments are concate-
              nated  together  with  space separators (just as in
              the concat command).  If there is a pending command
              that  matches  the string, it is cancelled and will
              never be executed;  if no such command is currently
              pending  then  the  after  cancel  command  has  no
              effect.

       after idle script ?script script ...?
              Concatenates the  script  arguments  together  with
              space  separators  (just as in the concat command),
              and arranges for the resulting script to be  evalu-
              ated  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
              command returns an identifier that can be  used  to
              cancel  the delayed command using after cancel.  If
              an error occurs while executing the script then the
              tkerror mechanism is used to report the error.

       after info ?id?
              This  command  returns  information  about existing
              event handlers.  If no  id  argument  is  supplied,
              then  the command returns a list of the identifiers
              for all existing  event  handlers  created  by  the
              after  command for this interpreter.  If id is sup-
              plied, 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 command 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


KEYWORDS
       cancel, delay, idle handler, sleep, time
