Re: [boost] [thread] A simply static initializeable mutex

From: Roland Schwarz (roland.schwarz_at_[hidden])
Date: 2006-10-30 04:09:18

Martin Bonner wrote:

> You may be able to do a little better.  The standard says "The storage
> for objects with static storage duration (3.7.1) shall be
> zeroinitialized (8.5) before any other initialization takes place."
> What is more, most normal operating systems give programs pages of
> memory that are zero-initialized, so compilers would have to do work to
> avoid this.

Sorry, I do not understand "so compilers would have to do work to
avoid this". Could you please try to state it with different
wording?

> I think that means you can declare constructors and STILL have the
> object well behaved.

Do you mean: the object might be already zero initialized before
the ctor runs? If yes: this is very dangerous to rely on!

1) "Might": the standard does not require it.

2) E.g.: MSVC initializes memory to "CDCDCDCDCDCD...." in debugging
    builds, so there is at least one prominent case where the
    assumption is false.

Roland