OW tools usage Overview

Open Watcom tools usage

Introduction

Open Watcom comes with a very efficient native 16-bit compiler supporting DOS and Win16 targets and a 32-bit x86 compiler targetting many different OSes (NT/Win32, OS/2, NetWare, Linux, ...). A major aim for the v2 development is support for x86_64 and ARM architectures. The most obvious "competitors" of Open Watcom would be the GCC-based Mingw-w64 for 32 Bit and 64 Bit Win32-targets, DJGPP for 32 Bit DOS targets and the ia16 port for 16 Bit DOS targets.

Comparisons to other (cross-)compilers

A striking difference compared to the binutils-based compilers (gcc, clang, pcc) when used as a cross compiler is that Open watcom only uses a single compiler (one for each target CPU architecture) and the target OS is determined by a compilation flag (see "cross compiling" below). Further, many OS-independent libraries lives in a generic architecture-specific location ($WATCOM/lib286 and $WATCOM/lib386) and only libraries with OS-specific features are put into OS-specific sub-directories - this is thanks to the Open Watcom C runtime that is distributed together with the compiler. This means that it is very easy to use a single install of Open Watcom as a cross compiler for a wide range of OSes. In contrast, a cross-compile toolchain based on binutils typically requires building a target-specific "trinity" of binutils, compiler and libc. Another advantage of Open Watcom as a cross compiler is that the resulting binaries and libraries integrate nicely with the target OS. For example, Python compiled with Open Watcom can load plugins compiled with Visual_C++. This is similar to how the different binutils-based compilers (often) can use libraries built with another binutils-based compiler. At this moment, the resulting binaries are not as optimized as those made by GCC.

OW tools description

16-bit x86 compilers

• wcc : the 16-bit "compile only" C compiler
• wpp : the 16-bit "compile only" C++ compiler
• wfc : the 16-bit "compile only" Fortran compiler
• wcl : the 16-bit "compile and link" utility for C/C++
• wfl : the 16-bit "compile and link" utility for Fortran
• owcc: the POSIX compatible "compile and link" utility. Set CC=owcc in a project depending on GNU makefiles.

The 16-bit x86 compilers finds its OS-independent libraries in the $WATCOM/lib286 directory and its OS-dependent libraries in $WATCOM/lib286/${target_os} sub-directory. Some OSes might need extra library paths, which can be added by the LIBPATH environment variable.

32-bit x86 compilers

• wcc386: the 32-bit "compile only" C compiler
• wpp386: the 32-bit "compile only" C++ compiler
• wfc386: the 32-bit "compile only" Fortran compiler
• wcl386: the 32-bit "compile and link" utility for C/C++
• wfl386: the 32-bit "compile and link" utility for Fortran
• owcc  : the POSIX compatible "compile and link" utility. Set CC=owcc in a project depending on GNU makefiles.

The 32-bit x86 compilers finds its OS-independent libraries in the $WATCOM/lib386 directory and its OS-dependent libraries in $WATCOM/lib386/${target_os} sub-directory. Some OSes might need extra library paths, which can be added by the LIBPATH environment variable.

(Cross-)compilation : Common settings

To cross compile, set the correct environment variables and a compile flag telling the compiler which target is intended. Without compile flags defining target, a native build is assumed.

By default OW is setup for native compilation "<compilation target> == <host system>" that for such compilation no extra setup is necessary. Following environment variables are setup per <installation>.

Variable	Value	Description
WATCOM	<path>	where OW installation is located <OW root>
WIPFC	<path>	where wipfc compiler supplementaly files are located <wipfc subdirectory>
EDPATH	<path>	where vi editor script files are located <eddat subdirectory>

Following environment variables are setup per <host system>.

Variable	Value	Description
PATH	<path>	add to PATH where OW host binaries are located, by example %WATCOM%\binw for DOS

For cross compilation following environment variables must be changed per <target system>.

Variable	Value	Description
INCLUDE	<path>	where target header files are located, by example %WATCOM%\h for DOS

DOS 16-bit target

compiler	target option
wcc	-bt=dos
wpp	-bt=dos
wfc
wcl	-bcl=dos
wfl	-l=dos or -lr
owcc	-bdos

Variable	host	Value
INCLUDE	Linux	$WATCOM/h
INCLUDE	non-Linux	%WATCOM%\h

DOS 32-bit target (with DOS 32-bit Extender)

compiler	target option	DOS Extender
wcc386	-bt=dos	any
wpp386	-bt=dos	any
wfc386		any
wcl386	-bt=dos -l=dos4g	DOS4GW
wcl386	-bt=dos -l=causeway	Causeway
wcl386	-bt=dos -l=dos32a	DOS32A
wcl386	-bt=dos -l=pmodew	PMODE/W
wfl386	-l=dos4g	DOS4GW
wfl386	-l=causeway	Causeway
wfl386	-l=dos32a	DOS32A
wfl386	-l=pmodew	PMODE/W
owcc	-bdos4g	DOS4GW
owcc	-bcauseway	Causeway
owcc	-bdos32a	DOS32A
owcc	-bpmodew	PMODE/W

Variable	host	Value
INCLUDE	Linux	$WATCOM/h
INCLUDE	non-Linux	%WATCOM%\h

Windows WIN16 16-bit or 32-bit targets

16-bit target

compiler	target option
wcc	-bt=windows
wpp	-bt=windows
wfc
wcl	-bcl=windows
wfl	-l=windows
owcc	-bwindows

32-bit target (with OW 32-bit WIN386 Extender)

compiler	target option
wcc386	-bt=windows
wpp386	-bt=windows
wfc386
wcl386	-bt=windows -l=win386
wfl386	-l=win386
owcc	-bwin386

Variable	host	Value
INCLUDE	Linux	$WATCOM/h:$WATCOM/h/win
INCLUDE	non-Linux	%WATCOM%\h;%WATCOM%\h\win

Windows WIN32 target (32-bit) Console Application

compiler	target option
wcc386	-bt=nt -bc
wpp386	-bt=nt -bc
wfc386
wcl386	-bcl=nt -bc
wfl386	-l=nt
owcc	-bnt -bc

Variable	host	Value
INCLUDE	Linux	$WATCOM/h:$WATCOM/h/nt
INCLUDE	non-Linux	%WATCOM%\h;%WATCOM%\h\nt

Windows WIN32 target (32-bit) Windowed Application

compiler	target option
wcc386	-bt=nt -bg
wpp386	-bt=nt -bg
wfc386
wcl386	-bt=nt -l=nt_win -bg
wfl386	-l=nt
owcc	-bnt_win -bg

Variable	host	Value
INCLUDE	Linux	$WATCOM/h:$WATCOM/h/nt
INCLUDE	non-Linux	%WATCOM%\h;%WATCOM%\h\nt

Linux target (32-bit only)

compiler	target option
wcc386	-bt=linux
wpp386	-bt=linux
wfc386
wcl386	-bcl=linux
wfl386	-l=linux
owcc	-blinux

Variable	host	Value
INCLUDE	Linux	$WATCOM/lh
INCLUDE	non-Linux	%WATCOM%\lh

OS/2 16-bit target

compiler	target option
wcc	-bt=os2
wpp	-bt=os2
wfc
wcl	-bcl=os2
wfl	-l=os2 or -lp
owcc	-bos2

Variable	host	Value
INCLUDE	Linux	$WATCOM/h:$WATCOM/h/os21x
INCLUDE	non-Linux	%WATCOM%\h;%WATCOM%\h\os21x

OS/2 32-bit target

compiler	target option
wcc386	-bt=os2
wpp386	-bt=os2
wfc386
wcl386	-bt=os2 -l=os2v2
wfl386	-l=os2v2
owcc	-bos2v2

Variable	host	Value
INCLUDE	Linux	$WATCOM/h:$WATCOM/h/os2
INCLUDE	non-Linux	%WATCOM%\h;%WATCOM%\h\os2

Netware target (32-bit)

compiler	target option
wcc386	-bt=netware
wpp386	-bt=netware
wfc386
wcl386	-bcl=netware
wfl386	-l=netware
owcc	-bnetware

Variable	host	Value
INCLUDE	Linux	$WATCOM/h:$WATCOM/novh
INCLUDE	non-Linux	%WATCOM%\h;%WATCOM%\novh

Some packages may need a proprietary set of libraries and headers from Novell.

RDOS target (32-bit)

compiler	target option
wcc386	-bt=rdos
wpp386	-bt=rdos
wfc386
wcl386	-bcl=rdos
wfl386	-l=rdos
owcc	-brdos

Variable	host	Value
INCLUDE	Linux	$WATCOM/rh
INCLUDE	non-Linux	%WATCOM%\rh