Watcom C

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Watcom C++ 11

The Watcom C language and compiler was really popular in the early 1990's because of its optimizations for the Pentium CPU, along with its ability to target MS-DOS, Windows 3.1, OS/2 in both 16bit and 32bit flavors. Watcom C also added the ability to target Novell Netware. Watcom C includes both register & stack calling compilers, which depending on the targeted CPU can yield better results.

You can find more information about Watcom on the OpenWatcom project page.


MS-DOS real mode support only


I'm pretty sure this version was for sale as a 16bit compiler. I've never seen it in the wild though.

C/386 7.0

I've been able to find some information on Dr. Dobbs magazine, detailing how version 7.0 introduced a 386 32bit specific version with support of Phar Lap's 386|DOS-Extender and Eclipse Computer Solutions' OS/386 extenders. Novell Netware 386 (which later became Netware 3) was also based on Watcom 7. 7.0 also relied on the extender's linker.


16-bit only.

C/386 8.0

Added native linker & debugging support, no longer relying on 3rd party tools.

C/386 8.5

Released in 1991? Adds support for Windows 3.0 (Win386 extender), OS/2 hosted executables, and the first version to includes the DOS/4GW extender, version 1.0 .

Download Watcom 8.5a.

Includes support for

  • Phar Lap
  • Ergo
  • Rational
  • AutoCad
  • 32-bit applications for Windows 3.0

By default doesn't include SDK components for OS/2 or Novel Netware.


Included support for OS/2 2.0, DOS & DOS 32bit. Also included was 486 optimizations. I think the 16-bit & 32-bit products were merged at this time.


C++, Windows NT host & target, and Pentium support added.


This version bundled the popular DOS/4GW DOS extender, and was made popular by such games as Doom. Version 10.0 included the Win32 SDK for Win32s & Windows NT 3.1, the Windows 3.1 SDK, and the OS/2 1.3 & 2.0 SDK's for OS/2 development. Additionally it included the MFC libraries. The last update to 10.0 was 10.6 from what I recall.


This updated the Windows NT support up to 3.5, and Windows 95 levels.


Watcom sold all the compiler technology to Sybase where it languished, then it was swept up by Powersoft. It was then open sourced, and is free to all including its FORTRAN.

The current version is 1.9


In the past year a fork, or OpenWatcom v2 has come to being. The current version is 2.0c which features hosting on Win64, and Linux.