Sun Studio C/C++/Fortran Compilers
- Resources for developers using C, C++, or Fortran.
- http://developers.sun.com/sunstudio/index.jsp

CIL - Infrastructure for C Program Analysis and Transformation
- CIL (C Intermediate Language) is a high-level representation along with a set of tools that permit easy analysis and source-to-source transformation of C programs.
- http://hal.cs.berkeley.edu/cil/

Pallyc Project
- Pallyc is a simplified C compiler that supports nested-function definition. Open-source project, source and binaries available.
- http://www.pallyc.org

MCPP
- A portable C/C++ preprocessor supporting several compiler-systems on UNIX and Windows. mcpp supports C99 and C++98 as well as C90 and it provides Validation Suite which tests C/C++ preprocessor comprehensively.
- http://mcpp.sourceforge.net/

Open Watcom
- Open Source project to maintain and enhance the Watcom C, C++ and Fortran Compilers.
- http://www.openwatcom.org/

TinyCC-Win32
- The small and fast C compiler usable as a library or exe. For I386 primarily. It also include linker and assembler. [Open source, LGPL]
- http://tinycc-win32.sourceforge.net/

Unicals Group
- A vendor of C/C++ development tools for OEM market.
- http://www.unicals.com/

Pelles C
- A complete IDE and development kit for Windows and Pocket PC. The compiler is based on LCC, and the install builder for Windows is based on NSIS. Both are heavily modified.
- http://www.smorgasbordet.com/pellesc/

Development Assistant for C
- IDE for Embedded Software development in ANSI C. Editor, Browser, Call-Hierarchy Graph, Software Metrics, Makefile Generator, Tool Integration. Interface to Debuggers and Version Control Systems.
- http://www.ristancase.com/dac/v40/

Ch
- A superset of C interpreter by SoftIntegration, Inc. It is the most complete C interpreter and an alternative to C compiler.
- http://www.softintegration.com/

LCC-Win32
- A compiler system for Windows 95 - NT, includes lcc, a development environment, and other tools.
- http://www.cs.virginia.edu/~lcc-win32/

Mix Software Inc
- Makers of Power C for DOS, Win32, and Linux. C++ addons, but no compiler
- http://www.mixsoftware.com/

Freeware for Solaris
- precompiled Gnu C and C++ binaries for Solaris, for Sparc and Intel architectures.
- http://www.sunfreeware.com/

lcc
- Retargetable ANSI C compiler for ALPHA, SPARC, MIPS R3000, Intel x86.
- http://www.cs.princeton.edu/software/lcc/

TenDRA
- The home of the open source TenDRA C/C++ compiler. [Open source, BSD]
- http://www.tendra.org/

Dunfield Development Systems
- Makers of freeware Micro-C compiler for DOS.
- http://www.dunfield.com/

Miracle C Compiler
- Runs under Windows 98/ME/2000/XP and compiles for DOS box/console. Provides a multi-window development environment with integrated compiler and linker.
- http://www.c-compiler.com/