Ah, cool, thanks for the info!
One last question:

Say I have lib1_test.c and lib2_test.c, both of which I want to convert into *.so files.
They both have a single function, say, run_test();
In lib1_test, run_test() echos "LIB1" to the screen, and in lib2_test, it echos "LIB2" to the screen. (For simplicity's sake.)

Obviously, with the same function, I can't have both in the same directory, because the program wouldn't know which run_test() I wanted. But, can I have one in place, run "test" with the one that uses "LIB1", then replace it with the one that displays "LIB2", and it will work? (i.e. does the executable look for specific filename and function in that file, or can they be interchanged?)

Sorry for the twisted question. Not exactly sure how to phrase what I'm asking.