Hi Vincent, You are right - the -Wconversion causes it to warn on that line. Is there any way to fix it ? 2 reasons : a) we are not allowed to have warnings in our code b) I am going to miss the real warnings about conversion if I let this pass. I just tried 1.48.0 with g++ 4.4.5 and 4.6 and same results. Without -Wconversion it is clean, but that is not an option for me. Not sure what is PO ? thx Neeraj ________________________________ From: boost-users-bounces@lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Vicente J. Botet Escriba Sent: Thursday, December 08, 2011 6:24 PM To: boost-users@lists.boost.org Subject: Re: [Boost-users] [boost] compilation warnings questions by a newbee Le 09/12/11 00:11, Marshall Clow a écrit : On Dec 8, 2011, at 2:58 PM, Rai, Neeraj wrote: Hi, I am writing my first boost program and having trouble with the compiler warning against boost 1.44.0. Is there any way to get rid of those warnings so I can focus on real warnings in my code ? The gist of warning is : boost_1_44_0/include/boost/mpl/aux_/integral_wrapper.hpp:73:96: warning: the result of the conversion is unspecified because '-0x00000000000000001' is outside the range of type 'boost::numeric::udt_builtin_mixture_enum' [-Wconversion] Any help or pointers are appreciated. Neeraj ====== The following program is a cut down version of my code, just declares sregex #include <iostream> #include <boost/xpressive/xpressive.hpp> int main (int _argc, const char** _argv) { std::cout << "argc=" << _argc << " argv=" << _argv << std::endl; using namespace boost::xpressive; std::string keyword(""); sregex const re(sregex::compile(keyword, sregex::icase)); } Just tried this with both gcc 4.2.1 and clang 3.0 using the current Boost (1.48), and it worked fine. No warnings, even with -Wall The PO is using -Wconversion Best, Vicente