# 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 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 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 procedure). 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 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 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 mechanism is used to report the error.

## SEE ALSO

tkerror

## KEYWORDS

cancel, delay, sleep, time