[plug] library version conflicts

[Mike Holland]

tim wrote:

> I have installed them to /usr/local/<libname>/  What is the best way to
> ensure that the app I am compiling uses the new version of the lib both
> at compile time and run time?

Libraries usually have a seperate package for compiling apps that use 
it. e.g. libfoo-2.1.rpm and libfoo-devel-2.1.rpm .
It helps to make sure the latter is not installed for redhat versions.

You should have the headers under /usr/local/include and libs in 
/usr/local/lib.  The app's Makefile should look in those places.

In the Makefile, you should see args to the compiler telling it
where to find headers ( -I ) and libraries (-L).
/usr/local/{include,lib} should be before /usr/{}

To check at run-time, "ldd <program>" will tell you which dynamic
libraries it uses.

Of course, Microsoft solved all these hassles long ago, by using
binary backward-compatible libraries called DLLs.