Watcom C/C++ compiler

Open Watcom
Original author(s) Watcom, Sybase,
SciTech Software
Developer(s) Open community
Initial release January 8, 2003
Stable release 1.9 / June 2, 2010
Development status Active
Written in C, C++
Operating system Cross-platform
Size 66 to 84 Mb
Type Integrated development environment
License Sybase Open Watcom Public License version 1.0
Website openwatcom.org

The Watcom C/C++ compiler is an open-source compiler for the computer programming languages C and C++ that produces executable programs for several platforms and operating systems.

Overview

Open source

Though no longer sold commercially by Sybase, the Watcom C/C++ compiler and the Watcom Fortran compiler have been made available as a gratis and questionably open source Open Watcom package with the assistance of SciTech Software.

The Open Source Initiative has approved the license while Debian, Fedora and the Free Software Foundation have rejected it. The code is portable and, like many other open source compiler projects such as GCC or LCC the compiler backend (code generator) is retargetable.

Operating systems

The compiler can be operated from, and generate executable code for, the DOS (MS-DOS, FreeDOS), OS/2, Windows, Linux operating systems. It also supports NLM targets for Novell NetWare. There is ongoing work to extend the targeting to Linux[1] 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.[2]

Uses

In the mid-1990s some of the most technically ambitious MS-DOS computer games such as Doom,[3] Descent,[3] Duke Nukem 3D,[3] and Rise of the Triad[4] were built using Watcom C/C++, some such as ROTT using the DOS/4GW protected mode extender with the Watcom compiler.

Variants

There is an unofficial fork[5] of Open Watcom V2 on GitHub.[6] A variant of the 16bit DOS CRT library startup was created with WASM.[7]

Compatibility with other compilers

Open Watcom's syntax supports many conventions introduced by other compilers, such as Microsoft's and Borland's, including differing conventions regarding (for instance) the number of leading underscores on the "asm" tag. Code written specifically for another compiler rather than standard-compliant C or C++ will often compile with the Watcom compiler.

Release history

The Open Watcom Wiki has a comprehensive history.[3]

Date Product Notes
1984 Waterloo C for S/370
1985 Work on current code generator codebase started
1988 Watcom C 6.0
  • DOS host and target only
  • Included a debugger and full set of runtime libraries
  • Generated better code than other compilers at the time
  • Watcom C Version 6.5 contained Graphics Library similar to Microsoft Graphics Library
1989 Watcom C 7.0
1989 Watcom C 7.0/386
1990 Watcom C 8.0
1990 Watcom C 8.0/386
1991 Watcom C 8.5
1991 Watcom C 8.5/386
1992 Watcom C 9.0
1992 Watcom C 9.0/386
  • OS/2 2.0 host and target support
  • 486 optimizations
  • Based pointer support
Watcom C 9.01/386
  • Windows 3.1 support
1993 Watcom C/C++ 9.5
1993 Watcom C/C++ 9.5/386
  • C++ compiler added
  • Pentium optimizations
  • Windows NT host and target support
1994 Watcom C/C++ 10.0
  • MFC included
  • Precompiled header support
  • 16-bit and 32-bit tools merged into single package
  • Redesigned debugger
  • C++ class browser added
  • Windows resource editors added
  • Graphical IDE for Windows and OS/2
1995 Watcom C/C++ 10.5
  • Native C++ exception handling on OS/2 and Win32
  • Windows 95 and NT 3.5 support
  • TCP/IP remote debugging
1996 Watcom C/C++ 10.6
  • Structured exception handling in C
  • Improved compatibility with Microsoft compilers
1997 Watcom C/C++ 11.0
  • Namespace, RTTI, and new style cast support in C++ compiler
  • 64-bit integer support
  • Multi-byte character support in libraries
  • Incremental linking support
  • COFF and ELF object file support in linker and librarian
  • Microsoft clone tools added
  • DLL based tools for better IDE integration
1998 Watcom C/C++ 11.0B
1999 Sybase issues end-of-life notice for Watcom C/C++ 11.0
2000 Sybase announces open sourcing of Watcom tools
2001-09-27 Watcom C/C++ 11.0c Beta
2002-12-21 Watcom C/C++ 11.0c
2003-01-28 Open Watcom 1.0
2003-08-12 Open Watcom 1.1
2004-01-07 Open Watcom 1.2
2004-08-03 Open Watcom 1.3
2005-12-14 Open Watcom 1.4
2006-04-26 Open Watcom 1.5
2006-12-15 Open Watcom 1.6
2007-08-18 Open Watcom 1.7
2007-10-23 Open Watcom 1.7a
2009-02-21 Open Watcom 1.8
2010-06-02 Open Watcom 1.9 Current Version

License considerations

The GNU project considers the Open Watcom license "nonfree" because "It requires you to publish the source code publicly whenever you “Deploy” the covered software, and “Deploy” is defined to include many kinds of private use."[8]

See also

References

  1. ↑ Installing Open Watcom on Linux - Open Watcom. OpenWatcom.org wiki.
  2. ↑ "Latest Release (June 2010) - Open Watcom". OpenWatcom.org wiki.
  3. ↑ 3.0 3.1 3.2 3.3 History - Open Watcom. OpenWatcom.com wiki.
  4. ↑ "RotT was written in Watcom C++ v10.0 with the Rational Systems DOS/4GW extender."
  5. ↑ "Open Watcom V2 Fork".
  6. ↑ "Open Watcom V2 Fork Project on GitHub".
  7. ↑ "pcdosasm.zip archive". 2010-07-27. Retrieved 2014-02-10. Modified Open Watcom C/C++ DOS 16-bit ..\STARTUP\DOS\CSTRT086.ASM code
  8. ↑ Free Software Foundation. "Various Licenses and Comments about Them". GNU Operating System. Retrieved Dec 23, 2014.

External links