[...] it is never stated anywhere in doc that alarm actually does not work on win32.

it is even worse. have a look into the windows quirks section. there is a list which contains all not-implemented functions on the win platform - the alarm () function is mentioned here.

the point is that alarm () does work (AS 5.8 804) in spite of being not implemented ... ;) on the other hand, why should unix specifics be implemented on an other platform?