Re: [Boost-users] [solved, somewhat] Re: [interprocess] garbage chars when extending interprocess strings?

Subject: Re: [Boost-users] [solved, somewhat] Re: [interprocess] garbage chars when extending interprocess strings?
From: Anthony Foiani (tkil_at_[hidden])
Date: 2011-08-01 06:13:13

Ion Gaztañaga <igaztanaga_at_[hidden]> writes:

> Please try SVN trunk code, I think it contains fixes for GCC
> optimizations.

Sure enough, it looks like this fixes it.  Stock GCC and Boost are
4.5.1 and 1.44.0, respectively:

  $ rpm -q gcc boost
  gcc-4.5.1-4.fc14.x86_64
  boost-1.44.0-8.fc14.x86_64

Updated versions are GCC 4.6.0 and trunk r73469:

  $ /usr/local/gcc/bin/g++ --version
  g++ (GCC) 4.6.0
  Copyright (C) 2011 Free Software Foundation, Inc.
  This is free software; see the source for copying conditions.  There is NO
  warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

  $ ( cd ~/Source/boost/trunk ; svn info )
  Path: .
  URL: http://svn.boost.org/svn/boost/trunk
  Repository Root: http://svn.boost.org/svn/boost
  Repository UUID: b8fc166d-592f-0410-95f2-cb63ce0dd405
  Revision: 73469
  Node Kind: directory
  Schedule: normal
  Last Changed Author: artyom
  Last Changed Rev: 73469
  Last Changed Date: 2011-08-01 02:04:27 -0600 (Mon, 01 Aug 2011)

Binaries:

  $ g++                                                  -O2 InterProcStringTest3.cpp -o InterProcStringTest3-gcc_4.5.1-boost_1.44.0-O2 -lpthread -lrt
  $ g++                    -isystem ~/Source/boost/trunk -O2 InterProcStringTest3.cpp -o InterProcStringTest3-gcc_4.5.1-boost_r73469-O2 -lpthread -lrt
  $ /usr/local/gcc/bin/g++                               -O2 InterProcStringTest3.cpp -o InterProcStringTest3-gcc_4.6.0-boost_1.44.0-O2 -lpthread -lrt
  $ /usr/local/gcc/bin/g++ -isystem ~/Source/boost/trunk -O2 InterProcStringTest3.cpp -o InterProcStringTest3-gcc_4.6.0-boost_r73469-O2 -lpthread -lrt

Results:

  $ for i in InterProcStringTest3-* ; do echo "=== $i ===" ; ./$i ; echo ; done

  === InterProcStringTest3-gcc_4.5.1-boost_1.44.0-O2 ===
  InterProcStringTest3.cpp(150): test sv1 == sv3 failed in function: 'int test_main(int, char**)'
  sv1="y\xffffffe2y", sv3="yyy"
  InterProcStringTest3.cpp(162): test sv1 == sv5 failed in function: 'int test_main(int, char**)'
  sv1="yyy\xffffffe2yy", sv5="yyyyyy"
  **** 2 errors detected

  === InterProcStringTest3-gcc_4.5.1-boost_r73469-O2 ===
  **** no errors detected

  === InterProcStringTest3-gcc_4.6.0-boost_1.44.0-O2 ===
  InterProcStringTest3.cpp(150): test sv1 == sv3 failed in function: 'int test_main(int, char**)'
  sv1="y\x03y", sv3="yyy"
  InterProcStringTest3.cpp(162): test sv1 == sv5 failed in function: 'int test_main(int, char**)'
  sv1="yyy\x03yy", sv5="yyyyyy"
  **** 2 errors detected

  === InterProcStringTest3-gcc_4.6.0-boost_r73469-O2 ===
  **** no errors detected

I'm actually somewhat surprised; I thought that 4.6.0 did the right
thing even with 1.44.0, but apparently not.

Either way, I think that I'm past this particular problem.

Thanks yet again for all the suggestions and other input.

Best regards,
Tony