variable - interrogate a button variable \f5variable var ?value? Variable queries or sets the value of a Tk radiobutton, checkbutton or choicebutton variable. An error diagnostic will be returned if the variable is of the wrong type (if for instance it is the name of a named channel).

If value is given, the value of the variable is set to that value, and any associated buttons will subsequently reflect this in their appearance. Omitting the value argument returns the current value of the variable.

The special variable lasterror holds the text of the last Tk error encountered. It resets when queried.

checkbutton (9), choicebutton (9), radiobutton (9)