From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Farine To: nobody@gcc.gnu.org Cc: gcc-prs@gcc.gnu.org Subject: Re: libstdc++/3584 Date: Sat, 07 Jul 2001 06:16:00 -0000 Message-id: <20010707131601.20916.qmail@sourceware.cygnus.com> X-SW-Source: 2001-07/msg00179.html List-Id: The following reply was made to PR libstdc++/3584; it has been noted by GNATS. From: Robin Farine To: gcc-gnats@gcc.gnu.org, gcc-prs@gcc.gnu.org, robin.farine@terminus.org, acnrf@dial.eunet.ch, gcc-bugs@gcc.gnu.org, nobody@gcc.gnu.org Cc: Subject: Re: libstdc++/3584 Date: 07 Jul 2001 15:13:04 +0200 This message improves the syntax and semantics of the description I have provided when I registered the bug report. Description: Routines such as atomic_add() that read a memory location, apply operations to the value read, use the swp instruction to update the memory location and swp again if the value read the 2nd time doesn't equal the value initially read, introduce a race condition. The attachment illustrates such a case. Robin http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view&pr=3584&database=gcc