[tz] Minor (unimportant really) technical UB bug in strftime() ?
Clive D.W. Feather
clive at davros.org
Wed Nov 9 23:07:06 UTC 2022
John Marvin via tz said:
> I'm not sure what the standard says about struct copies,
Footnote 42:
42)Thus, for example, structure assignment may be
implemented element-at-a-time or via memcpy.
This is in the context of:
When a value is stored in an object of structure or
union type, including in a member object, the bytes of the
object representation that correspond to any padding bytes
take unspecified values.42) The values of padding bytes
shall not affect whether the value of such an object is a
trap representation.
So if all the members of a structure hold object representations that
aren't trap representation, then structure copy is valid no matter how
implemented, though any padding bytes can change value unpredictably.
--
Clive D.W. Feather | If you lie to the compiler,
Email: clive at davros.org | it will get its revenge.
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