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Date: Thu, 19 Mar 2009 18:54:46 +0100
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: [1.7] /usr/bin no longer in default LD_LIBRARY_PATH
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On Mar 19 11:57, Yaakov S wrote:
> Corinna Vinschen wrote:
> >   From a POSIX perspective it's
> > wrong to rely on the default Win32 DLL load order in dlopen() and the
> > behaviour of dlopen() in 1.5.25 was a bug rather than a feature.

I spoke nonsense here.  See below.

> > Bottom line is, I'm sure the new behaviour is more correct, but if
> > you have a convincing argument to revert to the old behaviour, I'm
> > certainly open for discussion.
> 
> First, it's a huge regression.  This breaks *lots* of existing code.
> 
> Now, at risk of stating that which you already know quite well:
> 
> Using /usr/lib as the default LD_LIBRARY_PATH makes sense on *NIX
> platforms where the shared libraries are themselves in PREFIX/lib, and
> LD_LIBRARY_PATH is used not only by dlopen() but by ld.so for runtime
> linking as well.
> [...]
> How could we proceed?
> 
> We could keep the code as is, but since we install DLLs to /usr/bin and
> add it to PATH, we need to add it to LD_LIBRARY_PATH as well.  Those who
> add /usr/local/bin (or ~/bin) to their PATH will need to add it to their
> LD_LIBRARY_PATH also, so you end up with nearly identical PATH and
> LD_LIBRARY_PATH values.
> 
> OR we could revert the code to allow searching in PATH as before, since
> that's where the DLLs actually reside.

The SUSv4 dlopen man page clearly states

  "If file contains a <slash> character, the file argument is
   used as the pathname for the file. Otherwise, file is used
   in an implementation-defined manner to yield a pathname."

The best match for the implementation-defined manner under Cygwin
is probably the DLL search algorithm of Win32.

I'll revert that patch in a couple of minutes.


Thanks for the report,
Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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