API Tracer Level One
- http://www.geocities.com/ekhirin/
- Trap functions in DLL under Windows NT/2000/XP. Trapping engine is not limited in trapping DLL exports only and can trap any function, which address will be passed to it. [Freeware]
Etnus - Debugging Tools
- http://www.etnus.com/
- Developer of Totalview, a tool which aids in the development of multithreaded, multiprocess and network-distributed applications.
GDB: The GNU Debugger
- http://sources.redhat.com/gdb/
- Allows debug programs written in C, C++, and other languages, by executing them in a controlled fashion, and printing their data, on a wide variety of UNIX and non-UNIX systems.