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From: "gianni at mariani dot ws" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/13684] local static object variable constructed once but ctors and dtors called multiple times on same memory when called in multiple threads Date: Thu, 15 Jul 2004 05:11:00 -0000 [thread overview] Message-ID: <20040715051119.3730.qmail@sourceware.org> (raw) In-Reply-To: <20040114172507.13684.evijaykumar@yahoo.com> ------- Additional Comments From gianni at mariani dot ws 2004-07-15 05:11 ------- > It's not quite a one-time thing, of course: every time you run over > a static variable, you have to check whether it has already been > initialized. I suspect that this is done with the current gcc. > If this check has to be guarded by a lock, it gets vastly > more expensive than just checking for zero-or-one. I don't understand why you think so. Zack's suggestion (and this concept is also used in lots of other code) is this: if (guard) { if (__cxa_guard_acquire (&guard)) { // construct variable. __cxa_guard_release (&guard) } } The first conditional is not thread safe, however, once the object is correctly initialized the first conditional will be false and hence it will render code that is practically the same speed as non thread-safe code (code size will be larger, obviously!). -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13684
next prev parent reply other threads:[~2004-07-15 5:11 UTC|newest] Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top 2004-01-14 17:25 [Bug c++/13684] New: " evijaykumar at yahoo dot com 2004-01-14 17:27 ` [Bug c++/13684] " evijaykumar at yahoo dot com 2004-01-14 17:30 ` pinskia at gcc dot gnu dot org 2004-01-14 17:32 ` pinskia at gcc dot gnu dot org 2004-01-14 20:55 ` evijaykumar at yahoo dot com 2004-07-15 1:07 ` pinskia at gcc dot gnu dot org 2004-07-15 2:16 ` gianni at mariani dot ws 2004-07-15 2:42 ` bangerth at dealii dot org 2004-07-15 5:11 ` gianni at mariani dot ws [this message] 2004-07-15 11:07 ` rmerkert at alphatech dot com 2004-07-15 13:54 ` gianni at mariani dot ws 2004-08-21 0:01 ` jason at gcc dot gnu dot org 2004-08-28 2:34 ` cvs-commit at gcc dot gnu dot org 2004-08-28 10:18 ` pinskia at gcc dot gnu dot org 2004-08-28 19:04 ` gianni at mariani dot ws 2004-08-31 6:41 ` adah at netstd dot com 2004-08-31 20:58 ` pinskia at gcc dot gnu dot org 2004-09-01 16:58 ` cvs-commit at gcc dot gnu dot org 2004-09-04 18:06 ` jason at redhat dot com 2004-09-05 3:19 ` adah at netstd dot com 2005-04-13 16:56 ` dhruvbird at yahoo dot com 2005-04-14 7:39 ` jason at redhat dot com 2005-04-18 9:07 ` adah at netstd dot com 2005-04-18 18:28 ` jason at redhat dot com [not found] <bug-13684-4@http.gcc.gnu.org/bugzilla/> 2014-02-16 13:18 ` jackie.rosen at hushmail dot com
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