## Tcl8.6.0/Tk8.6.0 Documentation > Tk Commands, version 8.6.0 > tkwait

### Tcl/Tk Applications | Tcl Commands | Tk Commands | [incr Tcl] Package Commands | SQLite Package Commands | TDBC Package Commands | tdbc::mysql Package Commands | tdbc::odbc Package Commands | tdbc::postgres Package Commands | tdbc::sqlite3 Package Commands | Thread Package Commands | Tcl C API | Tk C API | [incr Tcl] Package C API | TDBC Package C API

### NAME

tkwait — Wait for variable to change or window to be destroyed

### SYNOPSIS

tkwait variable name
tkwait visibility name
tkwait window name

### DESCRIPTION

The tkwait command waits for one of several things to happen, then it returns without taking any other actions. The return value is always an empty string. If the first argument is variable (or any abbreviation of it) then the second argument is the name of a global variable and the command waits for that variable to be modified. If the first argument is visibility (or any abbreviation of it) then the second argument is the name of a window and the tkwait command waits for a change in its visibility state (as indicated by the arrival of a VisibilityNotify event). This form is typically used to wait for a newly-created window to appear on the screen before taking some action. If the first argument is window (or any abbreviation of it) then the second argument is the name of a window and the tkwait command waits for that window to be destroyed. This form is typically used to wait for a user to finish interacting with a dialog box before using the result of that interaction.

While the tkwait command is waiting it processes events in the normal fashion, so the application will continue to respond to user interactions. If an event handler invokes tkwait again, the nested call to tkwait must complete before the outer call can complete.

### SEE ALSO

bind, vwait

### KEYWORDS

variable, visibility, wait, window
Copyright © 1992 The Regents of the University of California. Copyright © 1994-1996 Sun Microsystems, Inc.