read(::IO, ::Ref) should be a method of read!

[JeffBezanson]

This mutates the Ref so should have a !.

[vtjnash]

Or make it a method of unsafe_read instead?

[JeffBezanson]

It seems equally safe as read! with an array argument, which we also have.

[vtjnash]

Except that Ptr <: Ref

[JeffBezanson]

Ah yes, that continues to confuse me. I think any operation that can write to a Ptr needs to contain unsafe_ if at all possible. So I think this should also be split into two methods. All in all I'd like:

• Define read!(::IO ::RefValue).
• Since unsafe_store! has a !, unsafe_read probably should too, so rename to unsafe_read!.
• Replace read(::IO, ::Ref) with unsafe_read!(::IO, ::Ptr).

This implies that Ptr should not really be a subtype of Ref, since otherwise any function with a ::Ref argument needs to have unsafe in its name. If we change that, then we can have read!(::IO, ::Ref).

[vtjnash]

otherwise any function with a ::Ref argument needs to have unsafe in its name

only if it then proceeds to call unsafe on that argument, in which case, of course? It's not unsafe to have a Ptr, only to load/store it

[JeffBezanson]

Yes, that's true. But I don't think you should have to call unsafe_read! to safely fill a RefValue. Bottom line, using the same generic function name where some argument cases are safe and others are unsafe is not ideal.