Is there a preprocessor for pointer size

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1

This is my code in C:

#if UINTPTR_MAX == 0xFFFFu
typedef uint16_t GRAINS_UINTPTR;
#elif UINTPTR_MAX == 0xFFFFFFFFu
typedef uint32_t GRAINS_UINTPTR;
#elif UINTPTR_MAX == 0xFFFFFFFFFFFFFFFFu
typedef uint64_t GRAINS_UINTPTR;
#endif

How would one implement this in Rust?

2

#[cfg(target_pointer_width)] is the answer to the title, but the code in question is just usize::MAX.

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3

The type you’re looking for is usize. Instead of GRAINS_UINTPTR you can just use usize, which is a pointer-sized integer.

The size of this primitive (usize) is how many bytes it takes to reference any location in memory. For example, on a 32 bit target, this is 4 bytes and on a 64 bit target, this is 8 bytes.

(There has been a lot of discussion over whether usize is size_t or uintptr_t that hasn’t really been resolved yet. AFAICT the “more correct” usage is usize = uintptr_t, but since it has “size” in the name and is also used for indexing, people also assume usize = size_t (and on mainstream platforms, uintptr_t = size_t)).

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