Compilers and the Rulbus Device Library
[User Manual]

This section describes some implementation details, that nonetheless may be important if you want to use the library with another compiler than Borland C++.

Compiler

The Rulbus Device Library has been developed with Borland C++ 5.6.
Some reasons for this are:

• it is a 32-bit Windows native compiler that supports the creation of DLLs well
• it supports standard C++ exception handling

There are at least two important aspects to this choice:

1. the library uses C++ exception handling internally
   GNU C++ does not support the C++ exception handling as specified in the C++ standard, so that it cannot be used to compile the library.
2. the rulbus.lib import library is in OMF format
   Borland C++ produces (import) libraries in OMF format, whereas GNU C and Visual C++ use (import) libraries in COFF format. There is no simple tool to convert an OMF import library to COFF, but an import library in COFF format, rulbus-coff.lib, is provided to use the library with a compiler other than Borland C++.

Calling convention

The Rulbus Device Library uses the cdecl calling convention. It is specified via the RDL_API preprocessor symbol in the function prototypes (rulbus.h) and definitions.

The calling convention is the arrangement of arguments for a procedure or function call. Different programming languages may require arguments to be pushed onto a stack or entered in registers in left-to-right or right-to-left order, and either the caller or the callee can be responsible for removing the arguments. The calling convention also determines if a variable number of arguments is allowed [foldoc].

Implicit linking a DLL requires an import library that is compatible with the compiler that is used to create a program. It is especially difficult to create an import library for Microsoft Visual C++ when the stdcall calling convention is used for the functions that are exported by the DLL created with Borland C++. Harold Howe's Creating DLLs in BCB that can be used from Visual C++ [BCBDEVDLL] shows how it can be done for both the cdecl and the stdcall calling convention.

Compiling programs

The following sections show how programs can be compiled using Borland C++, Microsoft Visual C++, GNU C and LabWindows/CVI.

Here, {include-path} specifies the directory with rulbus.h and rulbus-types.h and {library-path} specifies the directory with rulbus-omf.lib or with rulbus-coff.lib.

Borland C++

This compiler uses OMF library format.

bcc32 -I{include-path} -L{library-path} {program}.cpp rulbus-omf.lib

With Borland C++ version 5.6 you also can create a program that can be used without the DLL (standalone program). To this end the program is statically linked with the Rulbus Device Library, the Rulbus Device Class Library and the Windows Utilities Library.

bcc32 -tWM -I(include-path) -L{library-path} {program}.cpp \
   rulbus-omf-static.lib rulbusdcl-omf-static.lib winutils-omf-static.lib

Option -tWM specifies that the program must be linked with the multi-threaded C runtime library.

When you create a standalone program, you must inititialize the Rulbus Device Library yourself with rdl_initialize().

Visual C++

This compiler uses COFF library format.

cl -I{include-path} {program}.cpp /link -Libpath:{library-path} rulbus-coff.lib

GNU C

This compiler uses COFF library format.

g++ -I{include-path} -L{library-path} -o{program} {program}.cpp -lrulbus-coff

LabWindows/CVI

This compiler uses OMF/COFF ?? library format.

Todo:

find out how to use rulbus.dll with LabWindows/CVI

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