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Reply-To: moss AT cs DOT umass DOT edu
Subject: Re: Help debugging a dll issue
References: <b21c0ab1-341b-d6f5-915b-f73973b8079b AT cs DOT umass DOT edu> <CABHT960Yx_bg-NaHWcxePEV+Xz74NaVtsu+NjkrSZs4-62rCOA AT mail DOT gmail DOT com>
To: Sam Habiel <sam DOT habiel AT gmail DOT com>, "cygwin AT cygwin DOT com" <cygwin AT cygwin DOT com>
From: Eliot Moss <moss AT cs DOT umass DOT edu>
Message-ID: <3a4d2501-8845-99b6-d58b-544bff5e223f@cs.umass.edu>
Date: Fri, 20 May 2016 06:37:57 -0400
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On 5/19/2016 11:28 PM, Sam Habiel wrote:
> I had trouble with dlopen in Cygwin, where it did not behave intuitively. In my case, I was
> dlopening libicu and friends. If you search using my name on the Cygwin mailing list, you should be
> able to find out how I resolved the issue. I don't recall exactly what I did, but I think it was
> that Cygwin put everything in a global namespace, and you need to dlsym NULL to grab the function
> addresses.

I just tried using NULL for the handle in dlsym, and I get the same result as before, and it
does not change between using RTLD_LOCAL or RTLD_GLOBAL in dlopen.

What I am seeing is that looking up one symbol is giving the value for a totally different
one -- it's not returning an error indication.

And this same wrong value is what happens if I just allow the natural linking to take place
(which is what I really want to happen -- the dl calls simply help focus the issue).

I will look up your previous issue, though, to see if there is something else there of use
in this situation.

Regards -- EM

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