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Subject: Re: LLVM JIT based project fails due to undefined HAVE_DLOPEN
To: cygwin@cygwin.com
References: <trinity-f45c45ea-b5bd-4792-bcbb-3da58e7a2fb4-1525362137834@3c-app-gmx-bs61>
From: Norton Allen <allen@huarp.harvard.edu>
Message-ID: <4c0cdc2f-5d80-bca0-60c0-476a0745eeae@huarp.harvard.edu>
Date: Thu, 3 May 2018 19:54:25 -0400
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On 5/3/2018 11:42 AM, Ory Chowaw-Liebman wrote:
> Dear All,
>
> during my work on a programming language I noticed that with the update to LLVM 5.0.1
> the LLVM calls fail to find symbols defined in my executable.
> It used to work before the upgrade, and still works fine under windows.
> objdump lists the symbols wanted.
>
> With a lot of tracing through the LLVM code, I found that it depends
> on HAVE_DLOPEN being defined in a POSIX environment. When
> I call GCC with "-E -dM" only
> _GLIBCXX_HAVE_DLFCN_H
> is defined.
>
> Just using dlopen and friends from my code works fine (though there are o man pages).
> Should the macros HAVE_DLOPEN and HAVE_DLFCN_H not be defined?
>
> Thanks and best regards,
> Ory
>
Such symbols are not defined by the compiler. They are usually defined 
in a header file that is generated by a configuration script, perhaps 
one named 'configure', which might be generated by the autoconf program, 
possibly combined with other tools from the autotools package. You might 
need to dig into the configuration script to figure out why it decided 
you do not HAVE_DLOPEN or HAVE_DLFCN_H. Perhaps you need to install 
another package, or maybe the script is just broken. There should be a 
log file generated by the script with some details of its determinations.


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