Is there an equivalent in C for C++ templates?

Question

In the code I am writing I need foo(int, char*) and foo(int, int) functions.

If I was coding this in C++ I would use templates. Is there any equivalent for C? Or should I use void pointers? How?

Answer 1

I think the closest you can get in C to templates is some ugly macro code. For example, to define a simple function that returns twice its argument:

#define MAKE_DOUBLER(T)  \     T doubler_##T(T x) { \         return 2 * x;    \     }  MAKE_DOUBLER(int) MAKE_DOUBLER(float) 

Note that since C doesn't have function overloading, you have to play tricks with the name of the function (the above makes both doubler_int and doubler_float, and you'll have to call them that way).

printf("%d\n", doubler_int(5)); printf("%f\n", doubler_float(12.3)); 

Answer 2

You can't do that.
In C there are no overloads, one function, one name, you'll need to use a type that supports all your needs, e.g. (void *)

Either that or do a foo_int(int,int) and a foo_char(int, char*)