


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 ...?


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  delayed command is formed by concatenating 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 proce-
              dure).   If  an  error  occurs  while executing the
              delayed command then the tkerror mechanism is  used
              to  report the error.  The after command returns an
              identifier that can be used to cancel  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.

       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



Tk                             4.0                              1





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


              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 runs  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 mecha-
              nism is used to report the error.


SEE ALSO
       tkerror


KEYWORDS
       cancel, delay, sleep, time
