From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-203297-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 584 invoked by alias); 24 Nov 2006 13:43:43 -0000
Received: (qmail 547 invoked by uid 48); 24 Nov 2006 13:43:32 -0000
Date: Fri, 24 Nov 2006 13:43:00 -0000
Subject: [Bug other/29971]  New: anonymous namespace vs deprecated static keyword (different linkage).
X-Bugzilla-Reason: CC
Message-ID: <bug-29971-7667@http.gcc.gnu.org/bugzilla/>
Reply-To: gcc-bugzilla@gcc.gnu.org
To: gcc-bugs@gcc.gnu.org
From: "pluto at agmk dot net" <gcc-bugzilla@gcc.gnu.org>
Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-bugs.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-help@gcc.gnu.org>
Sender: gcc-bugs-owner@gcc.gnu.org
X-SW-Source: 2006-11/txt/msg02107.txt.bz2

in theory the anonymous namespace is a `static' keyword superior.
in fact it breaks applications that use dlopen() with RTLD_GLOBAL.
the so called superior emits symbols with different binding.

e.g.:

static keyword:
 00000000 4 OBJECT  LOCAL  DEFAULT  4 N::a_

namespace superior:
 00000000 4 OBJECT  GLOBAL DEFAULT  4 N::(anonymous namespace)::a_


$ make CPPFLAGS=-DSUPERIOR && ./main
i486-gnu-linux-g++ -Wall -O1 -g0 -s -DSUPERIOR *.cpp -c
i486-gnu-linux-g++ -Wall -O1 -g0 -s -DSUPERIOR m1.o A.o -o libm1.so -shared
i486-gnu-linux-g++ -Wall -O1 -g0 -s -DSUPERIOR m2.o A.o -o libm2.so -shared
i486-gnu-linux-g++ -Wall -O1 -g0 -s -DSUPERIOR main.cpp -o main -ldl
i486-gnu-linux-strip --strip-unneeded *.so main
i1 = 0x55b6b4
i2 = 0x55b6b4
Aborted

$ make && ./main
i486-gnu-linux-g++ -Wall -O1 -g0 -s  *.cpp -c
i486-gnu-linux-g++ -Wall -O1 -g0 -s  m1.o A.o -o libm1.so -shared
i486-gnu-linux-g++ -Wall -O1 -g0 -s  m2.o A.o -o libm2.so -shared
i486-gnu-linux-g++ -Wall -O1 -g0 -s  main.cpp -o main -ldl
i486-gnu-linux-strip --strip-unneeded *.so main
i1 = 0x759670
i2 = 0x112670


-- 
           Summary: anonymous namespace vs deprecated static keyword
                    (different linkage).
           Product: gcc
           Version: 4.1.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: other
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pluto at agmk dot net
GCC target triplet: elf-*


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29971