runtime determine type for C

Question

If the type of a variable must be determined as runtime in C but the variable name is fixed and given, is there any way to reuse the code that involves the variable?

Actually I am asking about the C counterpart situation of runtime determine type for C++.

If possible please give some examples.

Answer 1

The C language does not have the object-oriented features that make it meaningful to ask about the run-time type of an object in C++.

You typically implement genericity in C by casting to and from void*. Example: the C function qsort.

If your question is about determining at run-time what actual type a void* pointer points to, that's impossible. The information is simply not stored at all by most compilers.