Re: Probleme while loading libtool library

[Peter O'Gorman]

On Jun 13, 2007, at 2:58 AM, Laurent Marzullo wrote:

> Hello,
>
> I'm currently writing a program which load (with lt_dlopen) a  
> libtool library
> called 'liborapi.so'.
>
> This last library required 'libclntsh.so.10.1' which is an Oracle  
> 10i library.
>
> I've got an XML file where some attribute specify some additionnal  
> path to add
> to LD_LIBRARY_PATH
>
> I've then set this attribute to
> 1) The path where is located 'libcnltsh.so.10.1'
> 2) The path where is located 'liborapi.so'
>
> In my c++ program, I then use 'setenv' to modify LD_LIBRARY_PATH  
> with the 2 path
> above (Before doing the setenv, the LD_LIBRARY_PATH does not  
> countain any of the
> directory above).
>
> If I do:
>
> std::cerr << "LD_LIBRARY_PATH = " << getenv( "LD_LIBRARY_PATH" ) <<  
> '\n'

The dynamic linker tends to look at the environment variables at  
application startup only. Setting LD_LIBRARY_PATH in your application  
will have no effect on dlopen() et.al. until you exec() something.

People often write wrapper scripts that do nothing but set  
LD_LIBRARY_PATH (and their equivalents on other platforms) before  
execing the program, another alternative, would be to locate the  
library yourself, and pass lt_dlopen() the full path.

Lastly, there exists a libltdl specific search var, LTDL_LIBRARY_PATH,  
if you set this and explicitly lt_dlopen() both libraries in the right  
order i.e. lt_dlopen("libcnltsh.la") then lt_dlopen("liborapi.la")  
should work.

Hope this helps,
Peter
--
Peter O'Gorman
http://pogma.com