What is size_t in C?

Question

I am getting confused with `size_t` in C. I know that it is returned by the `sizeof` operator. But what exactly is it? Is it a data type?Let's say I have a `for` loop: for(i = 0; i < some_size; i++)Should I use `int i;` or `size_t i;`?

Answer 1

Hello there!

If you're curious to know what data type size_t is defined as, you'll find its definition in one of the include files (under /usr/include).

It's typically an unsigned int or long ...

Here's how it's defined by the system I'm currently using.

typedef unsigned int size_t;

But we shouldn't care what it is!

C has effectively abstracted this "size_t" data type for us - allowing our code to be immune to change or differences across systems.

We should use size_t when needing to define a like variable ... "unsigned int" today, something else tomorrow - we shouldn't need to care!