Re: [gentoo-user] Error with version of libraries with scilab

[Alan McKinnon]

On 09/10/2013 23:41, José Romildo Malaquias wrote:
> Hello.
>
> I have installed the *binary distribution of scilab* available form its
> download page.
>
> About two months ago, I was using it without problems.
>
> Now it does not work anymore. Running the binary gives the following
> error message:
>
> $ /alt/scilab-5.4.1/bin/scilab
> scilab-bin: /alt/scilab-5.4.1/lib/thirdparty/libz.so.1: version `ZLIB_1.2.3.4' not found (required by /usr/lib64/libpng16.so.16)
>
> I need helping understanding this message and fixing this issue on my
> ~amd64 system.
>
> Romildo
>



libpng16 is a library you already have on your system (not bundled with
scilab). And strangely, this *system* library is complaining that it
can't find the correct version of libz. These libs have names (sonames)
so you can tell different versions apart and use the right one.

But the system libpng has no business trying to use a third party app
under any circumstances. And in fact in regular use it doesn't, see mine:

$ ldd /usr/lib64/libpng16.so.16
        linux-vdso.so.1 (0x00007fff7d79a000)
        libz.so.1 => /lib64/libz.so.1 (0x00007ff9ad6ab000)
        libm.so.6 => /lib64/libm.so.6 (0x00007ff9ad3b5000)
        libc.so.6 => /lib64/libc.so.6 (0x00007ff9ad00a000)
        /lib64/ld-linux-x86-64.so.2 (0x00007ff9adb3c000)

See? system libpng uses system libz.

How does this happen? Easy. The authors of scilab are probably fiddling
with LD_LIBRARY_PATH, which just happens to be one of the more dangerous
things you can do in Unix.

Go find the startup script for scilab and edit the mods to
LD_LIBRARY_PATH to put the scilab directory at the end (not the
beginning where it is now)


-- 
Alan McKinnon
alan.mckinnon@×××××.com