xerces-c 2.8 : error while loading shared libraries - c++

Question

I'm trying to compile a program running on an HP UX server on a Red Hat Linux.
It uses xerces-c library to parse xml files. Compilation is ok, but when i try to run it, I get the following message
./a.out: error while loading shared
libraries: libxerces-c.so.28: cannot
open shared object file: No such file
or directory
I wrote a very simple program to try and understand whats going on:
#include <xercesc/util/PlatformUtils.hpp>
#include <xercesc/util/TransService.hpp>
#include <xercesc/parsers/SAXParser.hpp>
#include <xercesc/util/OutOfMemoryException.hpp>
int main(int argc, char* argv[])
{
return 0;
}
And compiled it like this:
g++ test.cpp
-L./xml/xerces-c_2_8_0/lib -lxerces-c -I./xml/xerces-c_2_8_0/include
Surprisingly the file is actually there:
lib]$ ls
libxerces-c.a libxerces-c.so.28 libxerces-depdom.a libxerces-depdom.so.28
libxerces-c.so libxerces-c.so.28.0 libxerces-depdom.so libxerces-depdom.so.28.0
Any thoughts ? I feel i'm missing something, but don't know what.
Thanks in advance.

Answer 1

run ldd a.out and see if the linker can resolve the right .so file
export LD_LIBRARY_PATH to include the current folder (in the same manner as the PATH variable) and check ldd again

Answer 2

the good way to do what you want is the following one:
g++ test.cpp -Xlinker -R ./xml/xerces-c_2_8_0/lib -lxerces-c -I./xml/xerces-c_2_8_0/include
or
g++ test.cpp -Wl,-rpath ./xml/xerces-c_2_8_0/lib -lxerces-c -I./xml/xerces-c_2_8_0/include
Xlinker or Wl options allow you to use specific linking options, you do not need to modifiy
LD_LIBRARY_PATH

Answer 3

You need to tell the runtime c library where to find the various symbols that arent compiled statically in your code and arent in the usualy /lib and /usr/lib locations.
You do this by adding the path to your shared library to LD_LIBRARY_PATH. In this case, this will be what you have been putting for the -L argument to the compiler.