[Haskell-cafe] Ghci dynamic linking (Was: C++ libraries and GHCI)

[Max Bolingbroke]

(Moving to ghc-users)

I'd never seen V in nm output before:

"""
The symbol is a weak object.  When a weak defined symbol is linked
with a normal defined symbol, the normal defined symbol is used with
no error.  When a weak undefined symbol is linked and the symbol is
not defined, the value of the  weak symbol becomes zero with no error.
 On some systems, uppercase indicates that a default value has been
specified.
""""

Perhaps support needs to be added for this symbol type to the GHCi
dynamic linker? (It would work in compiled programs b/c we call down
to the system static linker in that case).

Cheers,
Max

2009/9/29 Paolo Losi <paolo.losi at gmail.com>:
> Hi all,
>
> I would really appreciate if anyone could
> give a look to the following problem.
>
> Thanks in advance!!!
> Paolo
>
>
> ---------- Forwarded message ----------
> From: Paolo Losi <paolo.losi at gmail.com>
> Date: Mon, Sep 14, 2009 at 10:33 AM
> Subject: C++ libraries and GHCI
> To: glasgow-haskell-users at haskell.org
>
>
> Hi all,
>
> I'm working on a tentative implementation of haskell binding to libsvm [1]:
>
> http://hackage.haskell.org/package/HSvm
>
> The package includes libsvm C++ sources.
> While it works perfectly with ghc --make (try to install the package and
> compile http://bitbucket.org/pao/hsvm/raw/6cf7ca91f1e5/test/test.hs),
> it fails with ghci:
>
> (hsvm)(env)paolo at moltrasio:~/trash$ ghci test.hs
> GHCi, version 6.10.4: http://www.haskell.org/ghc/  :? for help
> Loading package ghc-prim ... linking ... done.
> Loading package integer ... linking ... done.
> Loading package base ... linking ... done.
> Ok, modules loaded: Main.
> Prelude Main> main
> Loading package syb ... linking ... done.
> Loading package array-0.2.0.0 ... linking ... done.
> Loading package containers-0.2.0.1 ... linking ... done.
> Loading package HSvm-0.1.0.2.89 ... linking ... <interactive>:
> /home/paolo/trash/hsvm/lib/HSvm-0.1.0.2.89/ghc-6.10.4/HSHSvm-0.1.0.2.89.o:
> unknown symbol `_ZTV6Kernel'
> ghc: unable to load package `HSvm-0.1.0.2.89'
>
> Please note that the symbol is available in libHSHSvm-0.1.0.2.89.a
>
> $ nm HSHSvm-0.1.0.2.89.o |grep _ZTV6Kernel
> 00000000 V _ZTV6Kernel
> $ nm libHSHSvm-0.1.0.2.89.a |grep _ZTV6Kernel
> 00000000 V _ZTV6Kernel
>
> Can anyone give a look to the problem?
>
> Thanks
> Paolo
>
> [1] http://www.csie.ntu.edu.tw/~cjlin/libsvm/
>
>
>
> --
> Paolo Losi
> e-mail: paolo at enuan.com
> mob:   +39 348 7705261
>
> ENUAN Srl
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