tk4.2 User Commands - tkwait
NAME
tkwait - Wait for variable to change or window to be des-
troyed
SYNOPSIS
tkwait variable name
tkwait visibility name
tkwait window name
DESCRIPTION
The tkwait command waits for one of several things to hap-
pen, then it returns without taking any other actions. The
return value is always an empty string. If the first argu-
ment 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 argu-
ment is visibility (or any abbreviation of it) then the
second argument is the name of a window and the tkwait com-
mand waits for a change in its visibility state (as indi-
cated 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.
KEYWORDS
variable, visibility, wait, window