Hello!
> Type punning is undefined behaviour. When you read from a different
> union member than you wrote to, there is no guarantee that you are
> actually reading the same memory.
I beg to disagree. Generally, type punning causes undefined behavior,
but there is a couple of specific cases explicitly allowed by the standard.
According to paragraph 6.5.7 of the C11 standard:
(1) A union containing a member of type T can be accessed as type T directly
(this also implies that union padding can be inserted only after the
members, not before).
(2) Any object can be accessed as (signed or unsigned) chars.
Have a nice fortnight
--
Martin `MJ' Mareš <[email protected]> http://mj.ucw.cz/
United Computer Wizards, Prague, Czech Republic, Europe, Earth, Universe
Hex dump: Where witches put used curses...
