When/where/why is a size_t not a uint?

Question

I've been getting a lot of criticism for using uint instead of size_t, but every time I check the toolchain I am working with turns out size_t is defined as a uint.

Are there any compiler implementations where size_t is actually not a uint? What are the grounds for that criticism?

Answer 1

size_t is the "size matching the largest possible address range you can use in the machine" (or some words to roughly that effect).

In particular, size_t will be 64 bits on a 64-bit machine, and 32 bits on a 32-bit system.

I'm assuming uint is short of unsigned int, which is pretty much universally 32 bits (these days, some older systems would be using 16-bit integers). So on a 64-bit system, an unsigned int will be 32 bits still, although memory allocations, strings, etc can be larger than 32 bits in size - which would cause problems if you are trying to use uint for the size.