Using Shared Object Files - c++

Question

I installed opencv 2.4.3 on ubuntu 12.04 using cmake. At the time of installation, .so files were put in /usr/local/lib directory. When I compile my code using the following line in terminal using the default location of .so files (i.e. /usr/local/lib) then it works fine
g++ fileName.cpp -lopencv_core -lopencv_highgui -lopencv_imgproc
I am trying to experiment with the shared object files. I copied the required shared object files from /usr/local/bin and put them in a new folder location /home/nishant/Desktop/lib. I copied the following files and their respective .so.2.4 and .so.2.4.3 files:
1) libopencv_core.so
2) libopencv_highgui.so
3) libopencv_imgproc.so
Then I changed there names to libcore.so , libhighgui.so and libimgproc.so respectively. I changed their name so that the old .so files should not be used from /usr/local/lib. Now when I try compiling my code using the shared object files in the new folder location then I get the following error:
Terminal Command:
g++ filename.cpp -L/home/nishant/Desktop/lib -lcore -lhighgui -limgproc
Error:
/usr/bin/ld: cannot find -lcore
/usr/bin/ld: cannot find -lhighgui
/usr/bin/ld: cannot find -limgproc
collect2: ld returned 1 exit status
It is interesting to note that the following works:
g++ filename.cpp -L/home/nishant/Desktop/lib -lopencv_core -lopencv_highgui -lopencv_imgproc
Reason: The .so files from /usr/local/lib are being used.
My Question : How can I use the .so files from the new folder location to make my code work.

Answer 1

I see three ways:
1.
Please update your LD_LIBRARY_PATH - add path to your libraries before running g++.
2.
Please add the directory where your libraries are located to /etc/ld.so.conf and run:
sudo ldconfig
Then run g++.
3.
Please create a new file: /etc/ld.so.conf.d/local.conf and add path do the directories with your libs to it and run:
sudo ldconfig
Then run g++.