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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug libstdc++/67434] std::chrono::duration acts like static even if instantiated every time Date: Wed, 02 Sep 2015 11:28:00 -0000 [thread overview] Message-ID: <bug-67434-4-J2QtUz1qTy@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-67434-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67434 Jonathan Wakely <redi at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution|--- |INVALID --- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Michal Kucharski from comment #0) > std::chrono::duration<double> benchmark( ) > { > std::random_device rd; > > std::chrono::duration<double> total; You have not initialized this variable. > > for (int i = 0; i < 100; i++) > { > auto t1 = std::chrono::high_resolution_clock::now(); > auto t2 = std::chrono::high_resolution_clock::now(); > total += std::chrono::duration_cast<std::chrono::duration<double>>(t2 - > t1); This has undefined behaviour because you are performing addition on an uninitialized value. You could have found this with valgrind.
next prev parent reply other threads:[~2015-09-02 11:28 UTC|newest] Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-09-02 11:15 [Bug libstdc++/67434] New: " sthlm58 at gmail dot com 2015-09-02 11:28 ` redi at gcc dot gnu.org [this message] 2015-09-03 11:55 ` [Bug libstdc++/67434] " sthlm58 at gmail dot com
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