Hello,

I'm having a few problems with boost::regex_replace seg faulting when used in a multithreaded program. The problem seems to be identical to the one described in http://lists.boost.org/boost-users/2006/06/20235.php, with a seg fault on line 133 of regex_format.hpp, though I have linked against the multithreaded version of libboost_regex.so and the problem is still happening. Unfortunately, I never saw any definitive answer for what was causing the original poster’s problems.

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Stack trace:

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Program received signal SIGSEGV, Segmentation fault.

[Switching to Thread -584664144 (LWP 28385)] 0x080520e0 in boost::re_detail::basic_regex_formatter<boost::re_detail::string_out_ite

rator<std::string>, boost::match_results<char const*, std::allocator<boost::sub_match<char const*> > >, boost::regex_traits_wrapper<boost::regex_traits<char,

boost::cpp_regex_traits<char> > > >::format_all (this=0xdd26b8d0) at

regex_format.hpp:133

133           switch(*m_position)

(gdb) where

#0  0x080520e0 in

boost::re_detail::basic_regex_formatter<boost::re_detail::string_out_ite

rator<std::string>, boost::match_results<char const*, std::allocator<boost::sub_match<char const*> > >, boost::regex_traits_wrapper<boost::regex_traits<char,

boost::cpp_regex_traits<char> > > >::format_all (this=0xdd26b8d0) at

regex_format.hpp:133

#1  0x080518be in

boost::re_detail::basic_regex_formatter<boost::re_detail::string_out_ite

rator<std::string>, boost::match_results<char const*, std::allocator<boost::sub_match<char const*> > >, boost::regex_traits_wrapper<boost::regex_traits<char,

boost::cpp_regex_traits<char> > > >::format (this=0xdd26b8d0, p1=0xd55005dc "$1", p2=0xd55005de "",

    f=format_all) at regex_format.hpp:123

#2  0x08051073 in

boost::re_detail::regex_format_imp<boost::re_detail::string_out_iterator

<std::string>, char const*, std::allocator<boost::sub_match<char const*>

>, char, boost::regex_traits_wrapper<boost::regex_traits<char,

boost::cpp_regex_traits<char> > > > (out=

      {<std::iterator<std::output_iterator_tag, char, int, char*, char&>> = {<No data fields>}, out = 0xdd26ba70}, m=@0xd5500518, p1=0xd55005dc "$1", p2=0xd55005de "",

    flags=format_all, t=@0x8064140) at regex_format.hpp:569

#3  0x08050710 in

format<boost::re_detail::string_out_iterator<std::basic_string<char,

std::char_traits<char>, std::allocator<char> > >, boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > > > (this=0xd5500518, out={<std::iterator<std::output_iterator_tag, char, int, char*, char&>> = {<No data fields>}, out = 0xdd26ba70},

    fmt=@0xdd26b990, flags=format_all, re=@0x805f6ec) at match_results.hpp:170

#4  0x0804fe35 in

boost::regex_replace<boost::re_detail::string_out_iterator<std::string>,

char const*, boost::regex_traits<char, boost::cpp_regex_traits<char> >,

char> (out=

      {<std::iterator<std::output_iterator_tag, char, int, char*, char&>> = {<No data fields>}, out = 0xdd26ba70}, first=0xd550048c "abcdefgh", last=0xd5500494 "", e=@0x805f6ec,

    fmt=0x805a2a9 "$1", flags=format_all) at regex_replace.hpp:53

#5  0x0804f7e1 in boost::regex_replace<boost::regex_traits<char,

boost::cpp_regex_traits<char> >, char> (s=@0xdd26ba80, e=@0x805f6ec,

fmt=0x805a2a9 "$1", flags=format_all)

    at regex_replace.hpp:84

#6  0x0804f3c4 in test_fn () at regexTest.C:32

#7  0xf63e5dec in start_thread () from /lib/tls/libpthread.so.0

#8  0xf6385a2a in clone () from /lib/tls/libc.so.6

(gdb) print *this

$1 = {m_traits = @0x8064140, m_results = @0xd5500518, m_out = {<std::iterator<std::output_iterator_tag, char, int, char*, char&>> = {<No data fields>}, out = 0xdd26ba70},

  m_position = 0xd44ff5d6 <Address 0xd44ff5d6 out of bounds>, m_end = 0xd55005de "", m_flags = format_all, m_state = output_copy, m_have_conditional = false}

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GCC version is 3.2.3 20030502 (Red Hat Linux 3.2.3-42), with Boost 1.33.1, on a 4 CPU machine.

We're using the STL from RogueWave, though since the post from a couple of weeks ago had the same problem with both GCC and STLport libraries I don't think that's the problem. This problem also occurs with version 1.33.0, but not with 1.32 or earlier.

Does anyone know if there is a known problem with using these new versions of boost::regex_replace in multiple threads? If it’s helpful, I have a very simple test program that demonstrates the problem. Any help on this would be greatly appreciated.

Kind regards,

Alistair Potts