Subject: Re: [Boost-users] [Review] Formal Review: Boost.Move
From: Ilya Sokolov (ilyasokol_at_[hidden])
Date: 2010-05-24 06:20:52
OvermindDL1 wrote:
> [snip]
>
> one (gcc related) bug-fix
> due to how this library implements something that is not well defined
> in the standard.
It is defined pretty clear (for me) in 3.8/6 of 14882:2003:
_quote_
Similarly, before the lifetime of an object has started but after the
storage which the object will occupy has
been allocated or, after the lifetime of an object has ended and before
the storage which the object occupied
is reused or released, any lvalue which refers to the original object
may be used but only in limited ways.
Such an lvalue refers to allocated storage (3.7.3.2), and using the
properties of the lvalue which do not
depend on its value is well-defined. If an lvalue-to-rvalue conversion
(4.1) is applied to such an lvalue, the
program has undefined behavior; if the original object will be or was of
a non-POD class type, the program
has undefined behavior if:
— the lvalue is used to access a non-static data member or call a
non-static member function of the object,
or
— the lvalue is implicitly converted (4.10) to a reference to a base
class type, or
— the lvalue is used as the operand of a static_cast (5.2.9) (except
when the conversion is ultimately
to char& or unsigned char&), or
— the lvalue is used as the operand of a dynamic_cast (5.2.7) or as the
operand of typeid.
_end_of_quote
> [snip]