Qt is a fantastically designed library. However, every now and then I think of something that I wish they offered that they don’t. It’s almost always something small and easily worked around, but it would be nice if it were just there. This time around, that feature is the ability to connect a signal to a function which is not a member of a class/struct. Specifically, I think it would be really cool if I could connect it to a c++0x lambda! Especially now that the ISO C++ committee approved the C++0x final draft.
The GNU Multiple Precision Arithmetic Library (GMP) is a wonderful library. It offers arbitrary precision math in a relatively simple, easy to use package. It is currently used in kcalc as the core for all basic math operations. The only problem is, the error handling it offers, is broken by design.