The most widespread family of operating systems on the planet, produced by [Microsoft] Corporation.

This Wiki has a fair amount of information on the subject of
[Microsoft Windows and Tcl] and [Microsoft Windows and Tk].

Interfacing to [Windows/CE] is something of a special case.
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"Despite being '''closed source''', holes are discovered '''constantly'''. "
[http://m.bacarella.com/papers/secsoft/html/index.html]