interface of dll -

i heard people talking changing interface of dll. change in interface of dll, , how that?

changing dll's interface mean change how dll , calling code interacts. mean changing signatures of dll's exporting functions, or changing different set of functions entirely, or mean passing different data calling code. dll's interface it's exported , imported items (both functions , data), or in other words, parts of dll have access when use it.

often want change behaviour of dll without changing interface. because changing interface break code uses it.

imagine dll exporting function foo:

void foo(int i) {    // thing integer }   

changing interface mean changing foo's signature into

void foo(int, float); 

now, code used foo has rewritten use new signature, bad thing.