Thread: arbitrary datatype arguments

Ok, so in C++ it is perfectly fine to have many functions with the same name, as long as they have a different set of parameters. In C, the rules are:
1. C only allows ONE function with a particular name, so you can not have more than one set of arguments to a function.
2. How is the function going to know what the arguments are?

You can sort use void * to pass a pointer to an arbitrary type. You still need some way to indicate WHAT type it is.

Variable argument functions can also take "any type" of argument (including non-pointer types), but again, you need some way to indicate what each type is, and how it should be used.

So, yes, there may be a way of doing this, but it's not entirely trivial.

--
Mats

Depending on the situation, the best way may be a macro. For example, let's use min() which returns the lower of its two arguments:

Code:

/* Notice the backslashes... */

#define DECLARE_MIN_FUNCTION_INSTANCE(type) \
void min_##type(type arg1, type arg2) \
{ \
    return (arg1 <= arg2) ? arg1 : arg2; \
}

Then, you could declare a min function for integers, and one for doubles:

Code:

/* Notice the lack of a trailing semicolon */

DECLARE_MIN_FUNCTION_INSTANCE(int)
DECLARE_MIN_FUNCTION_INSTANCE(double)

Unfortunately, you still need to invoke the function by its proper name. So if you are comparing ints, you would use min_int(), and for doubles you would use min_double(). I would not recommend this approach generally, but in certain cases it can be useful.

return type void looks suspicios