Copyright © 1998-2006 Dipl.-Inform. Kai Hofmann. All rights reserved!

DateLib (TM) portability

The DateLib (TM) is a high portable library, but it seems that nothing can be 100% portable without any modifications.

To make the library as portable as possible the following decision have been made:

• C/C++ has been used as implementation language, because C is available on nearly every platform - if you don't have a C compiler for a platform you can mostly use the freely available GCC.

  Another reason for using is that many other programming languages support an interface to C which allow it to use libraries as the DateLib is one.

• The datatypes used have been chosen carefully. For example it has been avoided to use 'int', because it's size is not well defined - it could be of 16 bit size or of 32. So we use short for 16 bit values and long for 32 bit values.

  Additionally 'unsigned' has been used wherever possible as well as 'const'. The big problem with a boolean datatype is, that C++ now defines one, but C does not. This has been solved by using #define's.

• #define's are used to increase the portability. The following #define's can be found within the system.h file:

  #define	Description
  bool	should be defined as 'short' when not working under ISO-C++
  true	should be defined as '1' when not working under ISO-C++
  false	should be defined as '0' when not working under ISO-C++
  VAR(n)	this macro will be used within function definitions/prototypes. It defines a variable as a pointer type (C) or as reference (C++)
  VAL(n)	This macro is used within a function body to access the value of a variable defined with VAR(n)
  ARG(n)	This macro must be used for VAR(n) parameters when calling such a function.
  INLINE	Allows the compiler to inline code - well defined for C++, but might be different for some C compilers.
  SNAME(n)	This macro is a work-around for the SAS Institute C compiler 'enum' bug. Should be empty as long as you are not using the SAS compiler.

  The following #define's are used to create shared libraries - normally you should leave them untouched:

  #define	Description
  ALIGNED	Align to next longword (4 byte)
  FAR	Use far data reference
  STACKARGS	Put function arguments onto the stack
  REGISTERARGS	Put function arguments into registers
  ASM	Required when using REG(r) or GCCREG(r)
  SAVEDS	Make sure that the dataspace pointer is set
  SAVEDS_ASM	Combination of SAVEDS and ASM
  DLL_EXPORT	Export function for Microsoft Windows® DLL
  DLL_IMPORT	Import function from Microsoft Windows® DLL
  D0-D7	680x0 data registers
  A0-A6	680x0 address registers
  REG(r)	Register definition
  GCCREG(r)	GCC register definition

  
  
  

  #define	Description
  INIT(modul,libbase)	System dependent init code
  CLEAN(modul,libbase)	System dependent cleanup code
  INITPROTO(modul,libbase)	System dependent init code prototype
  CLEANPROTO(modul,libbase)	System dependent cleanup code prototype
  INITCALL(modul,libbase)	Used to call the system dependent init code
  CLEANCALL(modul,libbase)	Used to call the system dependent cleanup code

• The following #define's are used for the optional debugging code - normally you should leave them untouched:

  #define	Description
  DEBUG	Debugging level
  DEBUG_PRINT_NEST	Used for indention
  DEBUG_PCHECK(condition)	Used for parameter checking
  DEBUG_ASSERT(condition)	Assert condition within program code
  DEBUG_ENTER(function name)	Enter function
  DEBUG_EXIT(function name, format template, return value)	Exit function
  DEBUG_VARDUMP(variable name, format template, variable value)	Dump variable
  DEBUG_POS	Source code position

• The following #define's are used for optional code:

  #define	Description
  DATE_NO_HEIS	Disable all "Heis" functions