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RedHat 9 (Linux i386) - man page for after (redhat section n)

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

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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?
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DESCRIPTION
       This  command  is  used to delay execution of the program or to execute a command in back-
       ground sometime in the future.  It has several forms, depending on the first  argument  to
       the command:

       after ms
	      Ms  must	be  an	integer giving a time in milliseconds.	The command sleeps for ms
	      milliseconds and then returns.  While the command is sleeping the application  does
	      not respond to 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 an event handler.  The command  will  be  exe-
	      cuted  exactly  once, at the given time.	The delayed command is formed by concate-
	      nating 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  bgerror
	      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 indi-
	      cates  which command should be canceled;	it must have been the return value from a
	      previous after command.  If the command 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 concatenated 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 evaluated later as  an
	      idle  callback.	The script will be run exactly once, the next time the 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 bgerror mechanism is used to report  the
	      error.

       after info ?id?
	      This  command returns information about existing event handlers.	If no id argument
	      is supplied, the command returns a list of the identifiers for all  existing  event
	      handlers	created by the after command for this interpreter.  If id is supplied, it
	      specifies an existing handler; id must have been the return value from some  previ-
	      ous  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.

       The after ms and after idle forms of the command assume	that  the  application	is  event
       driven:	the delayed commands will not be executed unless the application enters the event
       loop.  In applications that are not normally event-driven, such as tclsh, the  event  loop
       can be entered with the vwait and update commands.

SEE ALSO
       bgerror(n), concat(n), update(n), vwait(n)

KEYWORDS
       cancel, delay, idle callback, sleep, time

Tcl					       7.5					 after(n)


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