From mboxrd@z Thu Jan  1 00:00:00 1970
From: Yann E. MORIN <yann.morin.1998@free.fr>
Date: Mon, 29 Aug 2016 00:15:24 +0200
Subject: [Buildroot] [PATCH 2/2] package/sconeserver: needs shared libs
 or non uClibc toolchain
In-Reply-To: <87wpj07dga.fsf@dell.be.48ers.dk>
References: <1472408394-20573-1-git-send-email-yann.morin.1998@free.fr>
 <1472408394-20573-2-git-send-email-yann.morin.1998@free.fr>
 <87wpj07dga.fsf@dell.be.48ers.dk>
Message-ID: <20160828221524.GF5758@free.fr>
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To: buildroot@busybox.net

Peter, All,

On 2016-08-29 00:09 +0200, Peter Korsgaard spake thusly:
> >>>>> "Yann" == Yann E MORIN <yann.morin.1998@free.fr> writes:
> 
>  > sconeserver wants to use dlopen(), unconditionally: it does not try to
>  > detect it, and it can't work without it (the code is not conditional).
> 
>  > So, when the toolchain uses uClibc, and that uClibc has been configured
>  > with only static support, the dlopen() functions are not available at
>  > all, and the corresponding headers are not present:
> 
>  >     ModuleLoader.cpp:29:19: fatal error: dlfcn.h: No such file or directory
>  >      #include <dlfcn.h>
>  >                        ^
> 
>  > However, we can't know if uClibc has shared support or is static-only,
>  > especially for external toolchains.
> 
>  > The only way is to forbid the combination {uClibc,static}. So we may
>  > indeed forbid working combinations, for example if the external
>  > toolchain is uClibc-based and has support for shared libs...
> 
> Ehh, this I don't get. Why not simply depend on !BR2_STATIC_LIBS like we
> do for other users of dlfcn.h?
> 
> If BR2_STATIC_LIBS is enabled then there won't be any .so files in the
> target rootfs, so even if the C library has dlopen support it won't
> work.

Not necessarily true.

One can use dlopen() to load "addons" even from a staticaly linked
executable.

However, I don't care about sconeserver; I was just looking at build
failures and trying to make it the least broken as possible.

If you're fine with making it depend on non static-only and drop the
uclibc condition, that's fine with me. ;-)

Regards,
Yann E. MORIN.

> If an external (uClibc-based) toolchain has no shared library support
> then it can only be used in BR2_STATIC_LIBS configurations.
> 
> -- 
> Bye, Peter Korsgaard

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