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From: John Love-Jensen <eljay@adobe.com>
To: Sean MacLennan <seanm@seanm.ca>, MSX to GCC <gcc-help@gcc.gnu.org>
Subject: Re: G++ and constructors
Date: Tue, 06 Mar 2007 12:46:00 -0000	[thread overview]
Message-ID: <C212BE33.1D26D%eljay@adobe.com> (raw)
In-Reply-To: <45ECA343.5030306@seanm.ca>

Hi Sean,

> I don't need work-arounds, I just need to know if the code ever could be
> split.

Yes.  The code can be split (assuming that "lock()" and "unlock()" are not
performing some thread "critical protection" locking for you).

Although you didn't ask for work-arounds, here's a work-around that works
for GCC, but may not work in C++ in general*.

GCC uses threading protection for static objects.

So this variant of your routine, in GCC, should be thread safe:

----------------------------------------------------------------------
myclass* myclass::init_instance() // private: static
{
  return new myclass();
}

myclass* myclass::get_instance() // public: static
{
  static myclass* instance = InitInstance();
  return instance;
}
----------------------------------------------------------------------

HTH,
--Eljay

* since ISO 14882 C++ punted on the whole threading issue**.

** ... and on a standard C++ ABI, on modules, on... well, lots of stuff for
various reasons***.

*** some good reasons, some bad reasons -- depending on one's point of view.

  reply	other threads:[~2007-03-06 12:44 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-03-06  2:37 Sean MacLennan
2007-03-06 12:46 ` John Love-Jensen [this message]
2007-03-06 14:58   ` John Love-Jensen
2007-03-07 16:40   ` Daniel Lohmann
2007-03-08 17:16     ` Ian Lance Taylor

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