Updated 2011-12-21 11:41:24 by RLE

When an interpreter is created Tcl initializes this variable to hold the version number for this version of Tcl in the form x.y. Changes to x represent major changes with probable incompatibilities and changes to y represent small enhancements and bug fixes that retain backward compatibility. The value of this variable is returned by the info tclversion command. (from the "tclvars" manpage)