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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/52901] invalid rvalue reference Date: Sun, 08 Apr 2012 14:15:00 -0000 [thread overview] Message-ID: <bug-52901-4-88v4r3VotC@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-52901-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52901 Jonathan Wakely <redi at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution| |INVALID --- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-04-08 14:14:30 UTC --- This is just a bug in your program, not G++ (In reply to comment #0) > > X&& f() { > X x; > return std::move(x); > } This function is unsafe, it returns a reference to a local variable. You probably meant it to return X not X&& It is effectively the same as: X& f() { X x; return x; } (except G++ warns about that, because it's simpler) > > int main() { > cout << "Hello References [1]" << std::endl; > X x0 = f(); > cout << "x0: " << x0.value << std::endl; > X&& x1 = f(); This reference is bound to a variable that went out of scope when f() returned. > cout << "No copy construction or assignment expected" << std::endl; > cout << "x1: " << x1.value << std::endl; This accesses deallocated memory. N.B. you don't even need to use std::move, the compiler will automatically select the move constructor to create the return value here: X f() { X x; return x; }
next prev parent reply other threads:[~2012-04-08 14:15 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-04-07 16:35 [Bug c++/52901] New: " dieter.lucking at googlemail dot com 2012-04-08 13:49 ` [Bug c++/52901] " daniel.kruegler at googlemail dot com 2012-04-08 14:15 ` redi at gcc dot gnu.org [this message] 2012-04-08 15:33 ` marc.glisse at normalesup dot org 2012-04-08 18:06 ` redi at gcc dot gnu.org 2012-04-08 18:09 ` redi at gcc dot gnu.org
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