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From: Brian Salter-Duke <b_duke AT bigpond DOT net DOT au>
Subject:  Re: gcc4/gfortran
Date: Fri, 5 Dec 2008 10:28:00 +0000 (UTC)
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On Thu, 4 Dec 2008 14:35:02 -0500, Gustavo Seabra <gustavo DOT seabra AT gmail DOT com> wrote:
> On Wed, Dec 3, 2008 at 8:36 PM, Eric Blake wrote:
>> According to Gustavo Seabra on 12/3/2008 7:38 AM:
>>> 1. Is is safe to remove the old gcc (3.*) packages and replace them by
>>> symlinks to the new gcc4 executables?
>>
>> Read the archives.  Dave has mentioned that he is planning on a future
>> packaging of the gcc packages that use the alternatives package, so that
>> the symlink management of the name gcc can be done automatically to point
>> to either gcc-3 or gcc-4.  But at the moment, I'm not sure whether the
>> gcc-4 package requires files provided by the gcc package, in which case
>> blindly deleting all thing gcc 3.* might break gcc-4.
>>
>
> Got it. But I was actually just planning on removing the gcc and g77
> executables, and make those names point to gcc4 executables instead.
>
> It actually has nothing to do with disk space: the whole point is
> that, when compiling a program, I want to make sure it will *not* use
> g77, but gfortran instead. The way it is now, I have to specify
> gfortran-4 as the fortran compiler, say by using
> FC=/usr/bin/gfortran-4, but one can never be sure exactly how a
> specific 'configure' program will find its compilers. So, the removal
> of gcc/g77 executables and replacing by a symlink would remove any
> possibility for confusion.

That could lead to confusion as the arguments for gfortran are not
identical to those for g77. Myself, I want to have both to check that
code compiles OK with both them.

Brian.

>>> 2. In this case, which executables should I point the symlink to? For
>>> instance, if I were to replace g77 by a symlink to gfortran, which of
>>> the 4 gfortran executables should I use:
>>>
>>>     $ locate gfortran | grep exe
>>>     /bin/gfortran-4.exe
>>>     /bin/i686-pc-cygwin-gfortran-4.exe
>>
>> These are identical copies; one is the name preferred when
>> cross-compiling, the other when doing native compiles.
>
> Got it, thanks.
>
>> But why worry
>> about adding symlinks?  Why not just rely on what the package gave you,
>> since it works?  Are you really that low on disk space?  I suppose they
>> could be made hardlinks to one another, if someone were to invest the time
>> into patching setup.exe to attempt to make hardlinks (instead of its
>> current behavior of blindly creating identical copies, even when the tar
>> file specifies hardlinks).
>>
>>>     /usr/bin/gfortran-4.exe
>>>     /usr/bin/i686-pc-cygwin-gfortran-4.exe
>>
>> These two are identical to the ones above - you need to read the manual,
>> and remind yourself that /bin and /usr/bin are mount points that visit the
>> same directory.  Removing /bin/gfortran-4.exe would simultaneously make
>> /usr/bin/gfortran-4.exe disappear.
>>
>>>
>>> 3. Lastly, just a dumb question: why do we get multiple executables in
>>> the first place? I noticed that g77 also comes in multiple files:
>>>     $ locate g77 | grep exe
>>>     /bin/g77.exe
>>>     /usr/bin/g77.exe
>>>
>>> Is that really necessary?
>>
>> Yes, because that's how the default mount points are set up.
>
> OK, I had missed the point about /bin and /usr/bin actually pointing
> to the same directory. Things are a lot clearer now.
>
> Thanks,


-- 
       Brian Salter-Duke          Melbourne, Australia
     My real address is b_duke(AT)bigpond(DOT)net(DOT)au
Use this for reply or followup.  Registered Linux user 287938.
      Cygwin for Linux on PCs. <http://www.cygwin.com/>


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