[boost] [config] std::regex unusable on gcc?

Subject: [boost] [config] std::regex unusable on gcc?
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2014-03-22 12:00:28

Hi,

I'm trying to use std::regex and it's failing with even the simplest patterns:

  #include <regex>

  int main(int, char* argv[])
  {
    std::regex rex("\\d");
    return std::regex_match("1", rex);
  }

  g++ -std=c++11 rex_test.cpp -o rex_test
  ./rex_test
  terminate called after throwing an instance of 'std::regex_error'
    what():  regex_error
  Aborted (core dumped)

GCC version: gcc version 4.8.1 (Ubuntu/Linaro 4.8.1-10ubuntu9). GCC 4.7.3 
exhibits the same behavior.

Replacing "\\d" pattern with "[0-9]" results in the same failure. It works 
with Boost.Regex, Boost.Xpressive and with clang 3.4 & libc++. Am I doing 
something wrong?

If my use of std::regex is correct then for me this basically means that 
std::regex is unusable. In this case, could we define BOOST_NO_CXX11_HDR_REGEX 
in Boost.Config for all versions of libstdc++?