[Scilab-Dev] libscilab.so

[Sylvestre Ledru]

On 29/07/2013 23:59, vincent guffens wrote:
> Hi,
> 
> In order to call scilab from python, I used to create a module that
> links against libscilab.so. It turns out that this does not work anymore
> althought linking against libscilab-cli.so still works (without graphics
> obviously).
> 
> It looks like the library is now empty as shown with nm below while the
> same operation on libscilab-scli.so returns thousand of symbols.
> 
> $ nm -D /usr/local/lib/scilab/libscilab.so
>                w _Jv_RegisterClasses
> 0000200c  A __bss_start
>                 w __cxa_finalize
>                 w __gmon_start__
> 0000200c  A _edata
> 00002014  A _end
> 00000448  T _fini
> 000002f0  T _init
> 
> Is it an intented behaviour? Are the users supposed to link against all
> the individual needed shared libraries?
Actually, it depends how Scilab is built.

If it is built with --enable-maintainer-mode, each module will have it
own shared library (.so).
lld will show plenty of dependencies:
$ ldd modules/.libs/libscilab-cli.so|wc -l
89
$ readelf -s modules/.libs/libscilab-cli.so|wc -l
68

However, if we are building Scilab without the argument
--enable-maintainer-mode, it will build many modules as static library
and link them into a single shared libraries.

For example, when using the deb packages:
$ ldd /usr/lib/scilab/libscilab-cli.so|wc -l
44
$ readelf -s /usr/lib/scilab/libscilab-cli.so|wc -l
4102

One way or the other, in the first case, the linker should do the job of
loading the other libraries (ie -lscilab-cli or -lscilab should be
enough ... or not ;) )

Sylvestre