Create modal dialog and wait for response.
http://www.purl.org/tcl/home/man/tcl8.4/TkCmd/dialog.htm
See also: dialog.
The function can be found in the installed tcl/tk file dialog.tcl .
SYNOPSIS
tk_dialog window title text bitmap default string string ...
DESCRIPTION
This procedure is part of the Tk script library. Its arguments describe a dialog box:
After creating a dialog box, tk_dialog waits for the user to select one of the buttons either by clicking on the button with the mouse or by typing return to invoke the default button (if any). Then it returns the index of the selected button: 0 for the leftmost button, 1 for the button next to it, and so on. If the dialog's window is destroyed before the user selects one of the buttons, then -1 is returned.
While waiting for the user to respond, tk_dialog sets a local grab. This prevents the user from interacting with the application in any way except to invoke the dialog box.
Where you have a platform that should look (more or less) native on several platforms, use tk_messageBox in preference to this if possible and reasonable.
See also:
Category Dialog - Category Command - Tk syntax help - Arts and Crafts of Tcl-Tk Programming