Re: C code to Ada

["James S. Rogers" <jimmaureenrogers@worldnet.att.net>]

I looked in the GNAT file i-cstrea.ads. It defines the following
(just an excerpt from the file)

package Interfaces.C_Streams is
   pragma Preelaborate;

   --  Note: the reason we do not use the types that are in Interfaces.C is
   --  that we want to avoid dragging in the code in this unit if possible.

   subtype chars is System.Address;
   --  Pointer to null-terminated array of characters

   subtype FILEs is System.Address;
   --  Corresponds to the C type FILE*

   subtype voids is System.Address;
   --  Corresponds to the C type void*

It appears that you can correctly use System.Address on to
bind to a C void*.

Jim Rogers
"chris.danx" <spamoff.danx@ntlworld.com> wrote in message
news:e2_W9.3074$Ts5.30248@newsfep4-win.server.ntli.net...
> sk wrote:
> > Hi,
> >
> > I had a binding (lost due to a misplaced "mkfs /dev/...")
>
> oops!
>
> > but I am not sure where you are getting the "__THROW"
> > from.
>
> from /usr/include/dlfcn.h
>
>
> > When I was playing with shared-libraries etc (based on the
> > Linux-Documentation-Project Program-Library-HOWTO), I did
> > "man dlopen" and bound to the functions specified
> >
> >  From "man dlopen" ...
>
> Cheers will look at that!
>
>
> > #include <dlfcn.h>
> >
> > void *dlopen(const char *filename, int flag);
> >
> > So ...
> >
> >     ICS => Interfaces.C.Strings;
> >     IC  => Interfaces.C;
> >
> >     procedure Dlopen (
> >         Name : ICS.Chars_Ptr;  -- <= Assign with ICS.New_String
> >         Mode : IC.Int
> >     );
>
>
> I don't understand this.  Why procedure?  The return type of dlopen is
> not void (a procedure), but void* (a pointer to an unknown object -
> unknown to the client because dereferencing directly on void* isn't
> allowed; you have to cast it before you can dereference it).  It's where
> you get the handle from and what's causing me the most problems.
>
>
> >     procedure Dlsym (Handle : System.Address; Symbol : IC.Char_Array)
> >
> >     function Dlclose return IC.Int;
> >
> > Translating
> >     "(void)" typically translates to parameterless function/procedure
> >     "void function-name" typically translates to an Ada procedure
>
> See above.
>
>
> > The best source I found dealing with dl* is in the above mentioned
> > howto. With some care, the special library functions "init"
> > and "fini" can be nicely related to "adainit" and "adafinal"
> > needed to make a stand-alone shared/dynamic library all using
> > Ada and GNAT :-)
>
> I don't understand but I'll look at this a little later.
>
>
> Thanks,
> Chris
> --
> for personal replies change spamoff to chris
>