Is there any way to replace a function in a library?

Question

I work with a library which defines its internal division operator for a scripting language. Unfortunately it does not zero-check the divisor. Which leads to lot of headaches. I know the signature of the operator.

double ScriptClass::Divide(double&, double&);

Sadly it isn't even a C function. Is there any way I could make my application use my own Divide function instead of ScriptClass::Divide function?

EDIT: I was aware of dlopen(NULL,..) and replacing "C" functions with user defined ones. Can this be done for class member functions (Without resorting to using mangled names)?

Answer 1

Generally speaking it's up to the programmer, not the underlying divide operator to prevent division by zero. If you're dividing by zero a lot that seems to indicate a possible flaw in the algorithm being used. Consider reworking the algorithm, or if that's not an option, guard calls to divide with a zero check. You could even do that inside a protected_divide type function.

All that being said, assuming that since it looks like a C++ function you have a C++ library compiled with all the same options you're using to build your application so name mangling matches you might be able to redefine the function into a .so and use LD_PRELOAD to force it to load. If you link statically, I think you can create the function into your own .o file and linking that prior to the library itself will cause the linker to pick up your version.