'''`[http://tcl.tk/man/tcl/TkCmd/tkwait.htm%|%tkwait]`''', a built-in [Tk] [command], runs the [event loop] while waiting for something to happen (as described by its arguments).



** See Also **

   `[update considered harmful]`:   On the hazards of entering the event loop.

   [vwait]:   Similar to `tkwait variable`.



** Synopsis **


    :   '''[tkwait variable]''' ''name''

    :   '''[tkwait visibility]''' ''name''

    :   '''[tkwait window]''' ''name''



** Description **

While the `tkwait` 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.

[caspian]: Remember that tkwait syntax differs from `[after]`. With `after`, you need to enclose a command inside of `{` and `}`. To wit:

======
after 500 {
    puts "hello, world!"
}
======

With tkwait, there is no need to use `{ }`s. (You will get an error if you do). Instead, you can do something like this:

======
tkwait ...
puts "hello, world!"
======

Everything after `tkwait...` will not be executed until the event occurs.



** Gotcha: Global Scoping **

"Anyway, it's a little bit confusing that tkwait is 'scope-proof'. ;)" Another reminder to read the man page carefully: "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."



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