Re: Ada file depends on C file

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Thu, 17 Sep 2009 05:38:43 -0700 (PDT), mockturtle wrote:

> Dear all,
> I have a question that I am afraid is awfully trivial, but I spent
> half a morning without finding any answer.
> 
> My setup: I am working with GPS and I have an Ada procedure (say
> Interface_to_Addr in foo.adb) that needs to call a small C function
> (char *interface_to_ip (char*)) defined in interface_to_ip.c.  So, in
> my Ada code I wrote
> 
>    function interface_to_ip(interf : chars_ptr)  return chars_ptr;
>    pragma Import(C, interface_to_ip);
> 
> Everything compiles fine, but when it is time to link, the linker
> complains (correctly) that it cannot find "interface_to_ip".  The
> problem is that the compiler does not know that interface_to_ip is in
> interface_to_ip.c, or, in other words, it does not know that foo.adb
> depends on interface_to_ip.c.
> 
> Currently I solved by adding the line
> 
>     pragma Linker_Options("../../interface_to_ip.o");
> 
> and by compiling "by hand" interface_to_ip.c to interface_to_ip.o, but
> this solution is *UGLY*.
> 
> Everything would be fine if I could tell to the compiler that foo.adb
> depends on interface_to_ip.c, but I do not know how to do it.  I
> looked under the GPS "Project" menu, browsed the GNAT user & reference
> manuals (although not in the deepest detail) and googled for a while,
> but I could not find an answer.

The project file (*.gpr) has "package Linker". You can put linker options
there for example:

   package Linker is
      for Default_Switches ("ada")
         use ("-g", "-lgmem", <...further options...>);
   end Linker;

Alternatively, and probably better solution, would be to include the C
source into the project. AFAIK GPS supports C. In that case you should be
able to handle interface_to_ip.c exactly as you do Ada files.

BTW, never use GPS->Project->Edit Project Properties. Notepad is your
friend! (:-))

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de