How do I avoid implicit conversions on non-constructing functions?

Question

How do I avoid implicit casting on non-constructing functions?
I have a function that takes an integer as a parameter,
but that function will also take characters, b

Answer 1

You can't directly, because a char automatically gets promoted to int.

You can resort to a trick though: create a function that takes a char as parameter and don't implement it. It will compile, but you'll get a linker error:

void function(int i) 
{
}
void function(char i);
//or, in C++11
void function(char i) = delete;

Calling the function with a char parameter will break the build.

See http://ideone.com/2SRdM

Terminology: non-construcing functions? Do you mean a function that is not a constructor?