Re: Compiling, binding, and linking an Ada prog. interfaced with C

[fjh@cs.mu.oz.au (Fergus Henderson)]

eachus@spectre.mitre.org (Robert I. Eachus) writes:

>fjh@cs.mu.oz.au (Fergus Henderson) writes:
>
> > This is one respect in which Ada's otherwise excellent C interface
> > features are not quite as good as those of Mercury or ISE Eiffel,
> > which both allow you to import C macros without having to write a
> > separate C file containing glue code.
>
>   Huh?  The Ada way to imitate C in this area is to run the C
>preprocessor over your code and live with the result no matter how
>bizarre, just like it works in C.

I don't see how that technique could work as a method for interfacing
to existing C code, because typical C header files contain (in addition
to the macros that you want to interface with) lots of C declarations
which would not be valid Ada syntax.

Furthermore it would have the following problem that you mention yourself:

>Of course, if you have C macros
>that actually generate C source, then you can only use those inside
>units written in C.

Indeed.  And so trying to use them in Ada source files would be at
best a violation of encapsulation, and more likely simply wouldn't work.
Even simple things like hexadecimal and octal constants would be
a problem.

--
Fergus Henderson <fjh@cs.mu.oz.au>  |  "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh>  |  of excellence is a lethal habit"
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