Significant of struct repr

[ehsanmok]

Could example the significance of using the following pattern over ffi in your code vs. empty struct despite having the same size and alignment?

#[repr(C)]
pub struct MyStruct {
    _private: [u8; 0],
}

vs.

#[repr(C)]
pub struct MyStruct;

[LaurentMazare]

This actually comes from the ffi documentation. Specifically for the private field, this bit is interesting:

By including a private field and no constructor, we create an opaque type that we can't instantiate outside of this module. (A struct with no field could be instantiated by anyone.)

[ehsanmok]

I see! Thank you. It makes sense. That part must have been added somewhat recently.