Ushering out strlcpy()

There is no such thing as "just a number" in mathematics, even. An integer is a completely different sort of thing from a real number, or a rational number, or a complex number.

What is the result of calling the sine function on "a number"? What is the result of taking the square root of "a number"?

"Bigint" is a _very_ good default for a high-level programming or scripting language, for integers. But most of them keep using floating-point numbers despite their obvious flaws for a good reason: it's very hard to come up with anything else that will survive the kinds of operations people want to do on them.

You could use rational numbers, but there are lots of numbers people want to use that aren't rationals, and the fractional representations of rationals get huge very quickly when you use them. And even if you want to keep them only within a certain user-configured precision, knowing when to perform that reduction is not trivial if you want it to be performant (it shouldn't be after every operation).

Now there are other possible representations. You could represent numbers as functions that compute the value of the number to a given precision. You could represent numbers in many ways. What exactly a "number" is really isn't clear.