OpenEuphoria

Re: [OT] What is a 'header' file?

• Posted by Mario Steele <eumario at tri?a?e.net> Jun 04, 2008
• 753 views

ZNorQ wrote:
> 
> Derek Parnell wrote:
> > 
> > ZNorQ wrote:
> > > 
> > > I'm not quite sure what a header file is.
> > 
> > Header files are used by the C and C++ languages. 
> > 
> > They generally contain definitions that are used by a C/C++ program.
> > Specifically
> > they contain definitions of routines but without the actual details of the
> > routines'
> > implementation, just the name, return type, and parameter signature. For
> > example...
> > 
> >    int foo(char *, int);
> > 
> > This says that there is a routine called 'foo' that returns an 'int' and
> > accepts
> > as parameters a pointer to a 'char' and an 'int', declared somewhere else.
> > The
> > compiler uses this information so that when it comes across a call to the
> > routine,
> > it can validate the parameters on the call, and how the return value is
> > handled.
> > It can do this before it eventually comes across the actual routine's
> > implementation
> > details.
> > 
> > A header file might also contain struct and class definitions, but again it
> > doesn;t have to have implementation details, just the layout of the data
> > items
> > in them.
> > 
> > eg.
> > 
> >    class Bar {
> >        int abc;
> >        char* ddd;
> >        float xyz;
> >     }
> > 
> > Then, when the compiler comes across a reference to an object of the class
> > 'Bar',
> > it knows enough to check that the reference is valid.
> > 
> > Header files are useful for single pass compilers because it means that it
> > can
> > deal easily with forward references.
> > 
> > Header files are not needed for multiple pass compilers.
> > 
> > 
> > -- 
> > Derek Parnell
> > Melbourne, Australia
> > Skype name: derek.j.parnell
> 
> Ok. As for Euphoria, are we just talking about include files in general, or
> would there be a categorization between an include file containing a
> collection
> of procedures and functions, and those who acts like interfaces between Eu and
> DLLs? 
> 
> Kenneth/ZNorQ

In Euphoria, there is no specific "header" file type.  All includes contain code
in them.  There would be no need for that distinction.  You can write code to
link between Euphoria and a DLL/SO, directly into the main ex/exw/exu file, and
it would work just as fine, if you write it in a e/ew file.  So there's no direct
corilation between a "header" file that is used by C and Euphoria.

Mario Steele
http://enchantedblade.trilake.net
Attaining World Dominiation, one byte at a time...