OpenEuphoria

Re: how to write a wrapper?

• Posted by Jules <jdavy at dsl.?ipex?com> Aug 02, 2007
• 481 views

CChris wrote:
> 
> Jules wrote:
> > 
> > Andy wrote:
> > > 
> > > You should only be fine with a reference to c. Just go over some
> > > documentation
> > > of C and you should be fine
> > 
> > oh dear, I've been (politely) RTFM'ed. 
> > 
> > probably better if I post something specific. I'll get as far as I can and
> > when
> > stuck I'll return. 
> > 
> > Thanks anyway.
> 
> You need three things actually:
> 
> 1/ A fair idea of what the dll/so you wrap has inside. You'll get this
> knowledge
> from the documentation of the shared file, which may or may not be suitably
> organised. In some cases, feedback from users, if available, may help.
> 
> 2/ A fair idea of what the ysers of your wrapper would like to do with it, and
> which sort of pivture of what the hared lib handles they have. The most
> important,
> because you are the one who is going to translate the shared lib's ressources
> into stuff users may have interest in and can grok.
> 
> No C so far.

I suppose if the dll is well documented then it may be ok. 
> 
> 3/ The knowledge, from the documentation of the shared file, of the prototypes
> of the routines/vars you are going to use from the lib. You have to know what
> is a char, signed or not, a wchar, a tchar, an int and perhaps all sorts of
> fancy things. Pointers are well handled by the C_POINTER data type in the
> define_c_*()
> definition sequence, so the issue isn't as big as one would think. That's the
> only place some basic knowledge of C is needed.
> 
> Unless you need to understand the source of the lib, if available. That's
> another
> matter.
> 
> Also, remember that things are straightforward for shared libs coded in C, but
> not quite if they were output by a C++ compiler. I think the doc of fptr.e by
> M. Lewis contains useful information; I never tried it myself. Looking at the
> wxEuphoria wrappers is probably even more educational.

So it looks as though I'll need to at least understand C data types. I've been
looking in the archives and came across SWIG/Euphoria, which is supposed to
generate wrapper code. I haven't had a close look at it yet, but it seems as
though it may ease the burden.