Watcom C/C++ Compiler

The Watcom C/C++ compiler is a compiler for the computer programming languages C and C++ that produces executable programs for several platforms and operating systems. The code it produces for MS-DOS executes very fast. It was one of the first compilers to support the Intel 80386 "protected mode". In the mid-1990s some of the most technically ambitious DOS games such as Doom, Descent and Duke Nukem 3D were built using Watcom C.

Though no longer sold commercially by Sybase, the Watcom C/C++ compiler and the Watcom Fortran compiler have been made available as the free and open source Open Watcom package with the assistance of SciTech Software. The code is portable and, like many other open source compiler projects such as GCC or LCC the compiler backend (code generator) is retargetable. The compiler can be operated from, and generate executable code for, the DOS, OS/2, Linux and Windows operating systems. It also supports NLM targets for Novell NetWare. There is ongoing work to extend the targeting to Linux and modern BSD (e.g., FreeBSD) operating systems, running on x86, PowerPC and other processors. The Open Watcom C/C++ version 1.4 release on December 2005 introduced Linux x86 as an experimental target, supported from NT or OS/2 host platforms. There is code for an abandoned QNX version, but libraries necessary for it to be compiled could not be released as open source. Stable version 1.9 was released in June 2010.