Re: [Boost-users] narrowing conversion warning in boost's regex_traits_defaults.hpp when trying to initialize wregex object

Subject: Re: [Boost-users] narrowing conversion warning in boost's regex_traits_defaults.hpp when trying to initialize wregex object
From: John Maddock (boost.regex_at_[hidden])
Date: 2013-01-28 14:21:27

> The first line compiles ok. The second also produces working EXE, but in
> addition I get this large error:
>
>    In file included from d:\boost/boost/regex/v4/regex_traits.hpp:35:0,
>                     from d:\boost/boost/regex/regex_traits.hpp:27,
>                     from d:\boost/boost/regex/v4/regex.hpp:39,
>                     from d:\boost/boost/regex.hpp:31,
>                     from test.cpp:4:
>    d:\boost/boost/regex/v4/regex_traits_defaults.hpp: In instantiation of
> 'const charT* boost::re_detail::get_escape_R_string() [with charT =
> wchar_t]':
>    d:\boost/boost/regex/v4/basic_regex_parser.hpp:804:54:   required from
> 'bool boost::re_detail::basic_regex_parser<charT,
> traits>::parse_extended_escape() [with charT = wchar_t; traits =
> boost::regex_traits<wchar_t>]'
>    d:\boost/boost/regex/v4/basic_regex_parser.hpp:308:36:   required from
> 'bool boost::re_detail::basic_regex_parser<charT, 
> traits>::parse_extended()
> [with charT = wchar_t; traits = boost::regex_traits<wchar_t>]'
>    d:\boost/boost/regex/v4/basic_regex_parser.hpp:134:10:   required from
> 'void boost::re_detail::basic_regex_parser<charT, traits>::parse(const
> charT*, const charT*, unsigned int) [with charT = wchar_t; traits =
> boost::regex_traits<wchar_t>]'
>    d:\boost/boost/regex/v4/basic_regex.hpp:215:7:   required from 'void
> boost::re_detail::basic_regex_implementation<charT, traits>::assign(const
> charT*, const charT*, boost::re_detail::basic_regex_implementation<charT,
> traits>::flag_type) [with charT = wchar_t; traits =
> boost::regex_traits<wchar_t>;
> boost::re_detail::basic_regex_implementation<charT, traits>::flag_type =
> unsigned int]'
>    d:\boost/boost/regex/v4/basic_regex.hpp:661:4:   required from
> 'boost::basic_regex<charT, traits>& boost::basic_regex<charT,
> traits>::do_assign(const charT*, const charT*, boost::basic_regex<charT,
> traits>::flag_type) [with charT = wchar_t; traits =
> boost::regex_traits<wchar_t>; boost::basic_regex<charT, traits>::flag_type 
> =
> unsigned int]'
>    d:\boost/boost/regex/v4/basic_regex.hpp:382:33:   required from
> 'boost::basic_regex<charT, traits>& boost::basic_regex<charT,
> traits>::assign(const charT*, const charT*, boost::basic_regex<charT,
> traits>::flag_type) [with charT = wchar_t; traits =
> boost::regex_traits<wchar_t>; boost::basic_regex<charT, traits> =
> boost::basic_regex<wchar_t, boost::regex_traits&lt;wchar_t> >;
> boost::basic_regex<charT, traits>::flag_type = unsigned int]'
>    d:\boost/boost/regex/v4/basic_regex.hpp:367:48:   required from
> 'boost::basic_regex<charT, traits>& boost::basic_regex<charT,
> traits>::assign(const charT*, boost::basic_regex<charT, 
> traits>::flag_type)
> [with charT = wchar_t; traits = boost::regex_traits<wchar_t>;
> boost::basic_regex<charT, traits> = boost::basic_regex<wchar_t,
> boost::regex_traits&lt;wchar_t> >; boost::basic_regex<charT,
> traits>::flag_type = unsigned int]'
>    d:\boost/boost/regex/v4/basic_regex.hpp:336:7:   required from
> 'boost::basic_regex<charT, traits>::basic_regex(const charT*,
> boost::basic_regex<charT, traits>::flag_type) [with charT = wchar_t; 
> traits
> = boost::regex_traits<wchar_t>; boost::basic_regex<charT, 
> traits>::flag_type
> = unsigned int]'
>    test.cpp:15:37:   required from here
>    d:\boost/boost/regex/v4/regex_traits_defaults.hpp:329:73: warning:
> narrowing conversion of ''\37777777605'' from 'char' to 'const wchar_t'
> inside { } [-Wnarrowing]
>    d:\boost/boost/regex/v4/regex_traits_defaults.hpp:331:64: warning:
> narrowing conversion of ''\37777777605'' from 'char' to 'const wchar_t'
> inside { } [-Wnarrowing]

> ( and I know that this is the bug:
> https://svn.boost.org/trac/boost/ticket/7263 )

Do different issue - that relates to warnings generated by 
PTHREAD_MUTEX_INITIALIZER over which we have no control.

> so, any tricks to get around this (some compiler switches?, I dunno) ? Or
> can I just ignore this error ? (Yes I need regex matching on wide 
> strings.)

Just committed this patch for this: 
https://svn.boost.org/trac/boost/changeset/82662

HTH, John.