Libcwd is a full-featured and well-documented library that assists C++ developers with debugging their applications. It includes support for ostream-based debug output, custom debug channels and devices, memory allocation debugging, run-time sourcefile:linenumber information, and demangled type names of variables. It is thread-safe.
APD is a general purpose non-interactive PHP profiler/debugger that produces formatted strace/truss type reports. APD supports full stack backtraces via calls similar to croak() in Perl's carp. APD is a Zend Extension and is designed to provide timing with the minimal performance impact. APD supports varying levels of debugging and can be turned on/off in individual scripts.