According to the legal repercussions that came about
from the first MS//US DOJ
lawsuit there are to be _no_ undocumented function calls within the Microsoft
operating systems. If you are worried about function calls from the older
There
are MANY function calls inside even the most basic low-level
libraries for which no documentation exists.
For example, in user32.dll is the function RegisterUserAPIHooks. That is
totally undocumented.
That is just one example.
However, it is one of the many undocumented functions that only exist to
allow components of windows to talk to each other (in this case it exists
only to allow uxtheme/comctl32 to hook user32 and do non-client-area themeing).
The question is, do we implement such functions?