Cross platform General purpose C++ library

[William L. Hartzell]

Sir:

What, in your opinion, is the best general purpose C++ library? I am
looking for one that is BSD licensed or is public domain licensed. I
looked at IBM open classes, and they have a lot of what I want. But
they don't have cross platform implementations that I've found, nor meet
my license requirements. GUI & communication code is not important at
this time. Threads and message passing classes and the basics are wanted.
--
Bill
Thanks a Million!