C++ exception (and generic) stack trace library (now libinstrument)
... linked shared objects (DSO) and with any statically linked library. Libcsdbg helps the developer/tester also create stack traces of any thread, at any point during, as a snapshot of the runtime call graph. This is very useful in cases of fatal errors, reception of terminating signals or process abortion/termination (such as segmentation faults)
DUMA (Detect Unintended Memory Access) is a multi-platform memory debugging library. It can detect memory leaks and buffer overruns (or underruns) in a malloc() / new memory buffer. DUMA is a fork of Bruce Perens' Electric Fence library.
The XPS is a scalable platform for meta-programming and domain engineering. It provides a virtual machine, compiler, and runtime library that make it possible to efficiently develop, debug, and run programs based on XPL (eXtensible Programming Language)
Excellent macro based library to see program flow, variables, timings, errors, warnings. "Must have" for C/C++ programmers.