Re: Library file locations (was: Debian Policy for Ada, Second Edition)

[Tapio Kelloniemi <spam18@thack.org>]

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Pascal Obry <pascal@obry.net> wrote:
>Tapio Kelloniemi a �crit :
>
>> GNAT should look for project files in /usr/local as well, but I'm
>> afraid this will not be done. Perhaps the project file directory should be
>> changed to share/gnat.
>
>As I said this is not ok for handling multiple compilers. Remember that
>the libraries you build is dependent on the compiler version used to
>built it and can't be shared with another compiler.

This is not true. It is no more than a week when I upgraded GCC 4.0.2
to 4.1.0 on my Linux Ffrom Scratch system and I was able to upgrade glibc
with the new GCC without breaking anything. If all GCC's on the system target
the same architecture, one can compile libraries with one and applications
with another, if the compilers' ABI is the same.

> That's why having a root install directory per compiler version
> (/opt/gnat/<ver> or whatever) if a good scheme.

Yes it is, unless we are talking about the system Ada compiler. And back to my 
original idea of searching for project files in /usr/local/. You said that 
this can't be done, because multiple compilers must be supported. However GCC 
searches for header files in /usr/include and /usr/local/include even when it 
is installed under /opt. If some other behaviour is desired, GCC specs must be 
modified. So either GNAT should also use the same specs machanism as the rest 
of GCC (we agree that GNAT should behave the same way as other compilers in 
GCC?) or it should:
- Search from /usr/local if and only if it will be installed to /usr.
and/or
- Provide an easy way for system administrators to change the project search 
  path. Perhaps a file like ada_project_path could be added to lib/gcc/*/* 
  where ada_object_path and ada_source_path files may also reside.

-- 
Tapio