Re: using local static variable inside a function

From:

Pete Becker <pete@versatilecoding.com>

Newsgroups:

comp.lang.c++

Date:

Wed, 30 Sep 2009 15:29:23 -0400

Message-ID:

<yaKdnekR0fQJLF7XnZ2dnUVZ_hqdnZ2d@giganews.com>

SG wrote:

On 30 Sep., 16:25, Pete Becker wrote:

AnonMail2...@gmail.com wrote:

Static variable inside a function have compiler generated code that
makes sure the object is only constructed and initialized once. Since
standard C++ knows nothing about threads, the mechanism used to ensure
this is not thread safe.

Sorry, but that's a copout. If a compiler supports multiple threads,
then it should provide a thread-safe mechanism for initializing
function-static data objects. If it doesn't, don't blame the standard.
Blame the compiler.

If it doesn't it might still be a standards compliant compiler. I
think this was AnonMail's point.

Yes, of course it was. But the claim was:

    Since standard C++ knows nothing about threads,
    the mechanism used to ensure this is not thread safe.

The conclusion doesn't follow from the premise. The C++ standard does
not require that the initialization mechanism for function-static data
object not be thread safe.

--
   Pete
Roundhouse Consulting, Ltd. (www.versatilecoding.com) Author of
"The Standard C++ Library Extensions: a Tutorial and Reference"
(www.petebecker.com/tr1book)