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.
CMUCL is a free, high performance implementation of the Common Lisp programming language which runs on most major Unix platforms. It mainly conforms to the ANSI Common Lisp standard. CMUCL provides a sophisticated native code compiler; a powerful foreign function interface; an implementation of CLOS; the Common Lisp Object System; which includes multimethods and a metaobject protocol; a source-level debugger and code profiler; and an Emacs-like editor implemented in Common Lisp. CMUCL is maintained by a team of volunteers collaborating over the Internet, and is mostly in the public domain.
Code Medic provides access to the power of gdb with an intuitive front end. It currently supports opening multiple source windows at once, setting/clearing breakpoints while the program is running, watching variables change in the variable tree as you step through code (even with nested structs), text searching through source, and integration with Code Crusader to provide a rapid, efficient develop-debug cycle.
DBG is a PHP debugger and profiler. It makes it much easier to discover the origins of problems and bugs in PHP scripts. It's equipped with the ability to backtrace errors. It shows local and global variables as well as parameters which have been passed to all nested function calls at any point of execution. Among other things, it allows you to execute scripts in a step-by-step manner, set breakpoints (including conditional ones), evaluate expressions, and watch variables. The profiler allows you to find bottlenecks in PHP code at the functions level as well as the modules level and even the source lines level.
DUMA (Detect Unintended Memory Access) stops your program on the exact instruction that overruns (or underruns) a malloc() memory buffer. GDB will then display the source-code line that causes the bug. It works by using the virtual-memory hardware to create a red-zone at the border of each buffer: touch that, and your program stops. It can catch formerly impossible-to-catch overrun bugs. DUMA is a fork of Bruce Perens' Electric Fence library.
DieHard automatically hardens software applications against a wide range of bugs. These bugs, known as memory errors, often end up as serious security vulnerabilities, cause crashes, or lead to unpredictable behavior. DieHard either eliminates these bugs altogether, or avoids them with high probability.
MDK (MIX Development Kit) provides tools for developing and executing, in a MIX virtual machine, MIXAL programs. The MIX is Donald Knuth's mythical computer, described in the first volume of The Art of Computer Programming, which is programmed using MIXAL, the MIX assembly language. MDK includes a MIXAL assembler (mixasm), a MIX virtual machine (mixvm) with a command line interface, a Guile-based virtual machine (mixguile), a GTK+ based GUI (gmixvm), and a mixvm-Emacs interface (mixvm.el). MDK utilities are extensible using Scheme.
The GRASP Project has created an algorithmic-level graphical representation for software called the Control Structure Diagram (CSD). The CSD was created to improve the comprehension efficiency of Ada source code and, as a result, improve software reliability and reduce software costs. Since its creation, the CSD has been expanded and adapted to include other languages. GRASP provides the capability to generate CSD's from Ada 95, C, C++, Java, and VHDL source code in both a reverse and forward engineering mode with a level of flexibility suitable for professional application. GRASP has been integrated with the GNU family of compilers for Ada (GNAT) and C (gcc), and Sun's javac compiler for Java. Use of GRASP is not restricted to these compilers, however. This has resulted in a comprehensive graphically-based development environment for these languages. The user may view, edit, print, and compile source code as CSDs with no discernible addition to storage or computational overhead.
Java Development Environment for Emacs (JDEE) is an Emacs-based integrated development environment (IDE) for developing Java applications and applets. Features include multiple code browsers, a JPDA-based debugger, method and field completion, template-based and procedure-based code generation, Java source code interpreter, context-sensitive help, and more.