write-only not enforced about p4c HOT 5 CLOSED

Actually the spec does not say that they are write-only; just that they are uninitialized.
So I think that this program is correct.

from p4c.

So what does it mean to read from an uninitialized struct? Undefined behavior?

from p4c.

Yes, reading from an uninitialized variable or parameter produces an undefined value - but not an exception. So an out parameter is exactly like a local variable - initially uninitialized, but it's value at function termination is copied to the caller's corresponding argument.

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Seems like a trap that programmers will inevitably step into. (I just did.)

from p4c.

This is modeled after the C# out: https://msdn.microsoft.com/en-us/library/t3c3bfhx.aspx
We do copy-out instead of call by reference. In C# the variable may be uninitialized - in our case it is always uninitialized.

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