[Gambas-user] Problem with directory /lib

[craf]

-----Mensaje original-----
De: craf <prog at ...2177...>
Reply-to: mailing list for gambas users
<gambas-user at lists.sourceforge.net>
Para: Lista Gambas Ingles <gambas-user at lists.sourceforge.net>
Asunto: [Gambas-user] Problem with directory /lib
Fecha: Mon, 19 Apr 2010 11:15:32 -0400

>Hi.

>I managed to install a console program compiled on Ubuntu 9.04 to Ubuntu
>8.04, using shared libraries. 
>The problem is with a program that uses the GTK or QT library, and they
>require the libraries that are in the lib folder, and take into account
>that come with the PC and not those that are packaged with the project. 
>Example. If I provide shared libraries are located in the lib folder,
>should be exported with the following: 

>export LD_LIBRARY_PATH
>=/opt/proyect/gambas2/lib_shared/lib:/opt/proyect/gambas2/lib_shared/usr/lib 

>The path /usr/lib is taken into account, but the path /lib, and take the
>PC where you are installing the program. 

>I also tested:

>export LD_LIBRARY_PATH =
>$LD_LIBRARY_PATH:/opt/proyect/gambas2/lib_shared/lib:/opt/proyect/gambas2/lib_shared/usr/lib

>export LD_LIBRARY_PATH
>=/opt/proyect/gambas2/lib_shared/lib:/opt/proyect/gambas2/lib_shared/usr/lib:$LD_LIBRARY_PATH

>but nothing...

>Is there any way to force you to take the path /lib specified in the
>file .sh by one and not the PC?

>Regards
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Hi.

Searching the Internet the reason why the put the path to the
folder /lib in the LD_LIBRARY_PATH variable is not taken into account,
if you take into account the /lib of the computer where the program is
being installed with shared libraries.

He added explanation found:

----------------------------------------------------------------------
"It is very possible to have multiple versions of glibc on the same
system (we do that every day).

However, you need to know that glibc consists of many pieces (200+
shared libraries) which all must match. One of the pieces is
ld-linux.so.2, and it must match libc.so.6, or you'll see the errors you
are seeing.

The absolute path to ld-linux.so.2 is hard-coded into the executable at
link time, and can not be easily changed after the link is done.<---THAT
IS THE PROBLEM¡¡¡

To build an executable that will work with the new glibc, do this:

g++ main.o -o myapp ... \
   -Wl,-rpath=/path/to/newglibc \
   -Wl,-dynamic-linker=/path/to/newglibc/ld-linux.so.2

The -rpath linker option will make the runtime loader search for
libraries in /path/to/newglibc (so you wouldn't have to set
LD_LIBRARY_PATH before running it), and the -dynamic-linker option will
"bake" path to correct ld-linux.so.2 into the application."

source:http://stackoverflow.com/questions/847179/multiple-glibc-libraries-on-a-single-host/851229#851229
----------------------------------------------------------------------------------------

In short, if I want to be transported for example ld-linux.so.2 file
from a computer with Ubuntu 9.10 to another distribution that does not
have the same version. I can only do so if at compile Gambas added
routes where I have copied my shared libraries, so that then can be
called with the variable LD_LIBRARY_PATH.

Now, I saw also that you can use the LD_PRELOAD variable, Can I use?.

Regards.