Daniel James wrote:

On 14 August 2010 06:35, Vladimir Prus wrote:

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John Dlugosz wrote:

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A little experimenting tells me that it doesn't like having spaces in the string! Note that the quotes are understood by the run-time library that calls main, so the whole string (without surrounding quotes) is present in one element of argv. It works just fine when taking the argument as a string.

This seems like a bug, somewhere.

Try:

lexical_castfs::wpath(fs::wpath("the path that fails"))

If that fails, it means operator>> is mishandling spaces in paths.

If this filesystem v2 or v3? In filesystem v3, the stream extractor uses whitespace as a separator (correctly IMO), so filenames with spaces have to be quoted. I suspect the issue is that the filename has already have been unquoted by the shell.

Your test will work, since the filename is quoted as it's written to the stream, and then unquoted as it's extracted. But you'll see the error with:

lexical_castfs::wpath("the path that fails")

Does program options ever do that?

Yes, of course. It takes string from command line, and does lexical_cast on it. So, it seems like the only approach is to specialize lexical_cast for wpath/path? - Volodya

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       lexical_castfs::wpath(fs::wpath("the path that fails"))

Making the string literal a L-string (L"the path that fails"), it won't compile. The spiel is attached at the end of this message.

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If that fails, it means operator>> is mishandling spaces in paths.

lexical_castfs::wpath("the path that fails")

Correcting to make the string L, it throws an exception "bad lexical cast: source type value could not be interpreted as target" You ask if it's version 2 or version 3 of the fs library: It doesn't say! However, the href for the docs says "this is version 2", which was "default for Boost 1.44 only". But I have Boost 1.43. The headers don't show version numbers, but do show a date of 2005. Should I move to version 3? I guess Boost 1.44 is hot off the press so it's normal enough that I don't have it? === Compiler output for line 13 which is fs::wpath p1= lexical_castfs::wpath(fs::wpath(L"the first path that fails")); Microsoft (R) C/C++ Optimizing Compiler Version 15.00.30729.01 for x64 Copyright (C) Microsoft Corporation. All rights reserved. fs_test.cpp D:\boost_1_43_0\boost\lexical_cast.hpp(595) : error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'const src' (or there is no acceptable conversion) C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(653): could be 'std::basic_ostream<_Elem,_Traits> &std::operator <<(std::basic_ostream<_Elem,_Traits> &,const char *)' [found using argument-dependent lookup] with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(700): or 'std::basic_ostream<_Elem,_Traits> &std::operator <<(std::basic_ostream<_Elem,_Traits> &,char)' [found using argument-dependent lookup] with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(738): or 'std::basic_ostream<_Elem,_Traits> &std::operator <<(std::basic_ostream<_Elem,_Traits> &,const char *)' [found using argument-dependent lookup] with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(785): or 'std::basic_ostream<_Elem,_Traits> &std::operator <<(std::basic_ostream<_Elem,_Traits> &,char)' [found using argument-dependent lookup] with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(909): or 'std::basic_ostream<_Elem,_Traits> &std::operator <<(std::basic_ostream<_Elem,_Traits> &,const signed char *)' [found using argument-dependent lookup] with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(916): or 'std::basic_ostream<_Elem,_Traits> &std::operator <<(std::basic_ostream<_Elem,_Traits> &,signed char)' [found using argument-dependent lookup] with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(923): or 'std::basic_ostream<_Elem,_Traits> &std::operator <<(std::basic_ostream<_Elem,_Traits> &,const unsigned char *)' [found using argument-dependent lookup] with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(930): or 'std::basic_ostream<_Elem,_Traits> &std::operator <<(std::basic_ostream<_Elem,_Traits> &,unsigned char)' [found using argument-dependent lookup] with [ _Elem=char, _Traits=std::char_traits<char> ] D:\boost_1_43_0\boost/filesystem/path.hpp(584): or 'std::basic_ostream<_Elem,_Traits> &boost::filesystem::operator <<<T>(std::basic_ostream<_Elem,_Traits> &,const Path &)' [found using argument-dependent lookup] with [ _Elem=wchar_t, _Traits=std::char_traits, T=src, Path=src ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(170): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::basic_ostream<_Elem,_Traits> &(__cdecl *)(std::basic_ostream<_Elem,_Traits> &))' with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(176): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::basic_ios<_Elem,_Traits> &(__cdecl *)(std::basic_ios<_Elem,_Traits> &))' with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(183): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::ios_base &(__cdecl *)(std::ios_base &))' with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(190): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::_Bool)' with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(210): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(short)' with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(243): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(unsigned short)' with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(263): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(int)' with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(288): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(unsigned int)' with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(308): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(long)' with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(328): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(unsigned long)' with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(349): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(__int64)' with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(369): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(unsigned __int64)' with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(390): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(float)' with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(410): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(double)' with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(430): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(long double)' with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(450): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(const void *)' with [ _Elem=char, _Traits=std::char_traits<char> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(470): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::basic_streambuf<_Elem,_Traits> *)' with [ _Elem=char, _Traits=std::char_traits<char> ] while trying to match the argument list '(std::basic_stringstream<_Elem,_Traits,_Alloc>, const src)' with [ _Elem=char, _Traits=std::char_traits<char>, _Alloc=std::allocator<char> ] D:\boost_1_43_0\boost\lexical_cast.hpp(594) : while compiling class template member function 'bool boost::detail::lexical_stream::operator <<(const Source &)' with [ Target=boost::filesystem::wpath, Source=src, Traits=traits ] D:\boost_1_43_0\boost\lexical_cast.hpp(1148) : see reference to class template instantiation 'boost::detail::lexical_stream' being compiled with [ Target=boost::filesystem::wpath, Source=src, Traits=traits ] D:\boost_1_43_0\boost\lexical_cast.hpp(1174) : see reference to function template instantiation 'Target boost::detail::lexical_cast(const boost::filesystem::basic_path &,CharT *,size_t)' being compiled with [ Target=boost::filesystem::wpath, String=std::wstring, Traits=boost::filesystem::wpath_traits, CharT=char_type ] fs_test.cpp(13) : see reference to function template instantiation 'Target boost::lexical_cast>(const Source &)' being compiled with [ Target=boost::filesystem::wpath, String=std::wstring, Traits=boost::filesystem::wpath_traits, Source=boost::filesystem::basic_pathstd::wstring,boost::filesystem::wpath_traits ] D:\boost_1_43_0\boost\lexical_cast.hpp(595) : error C2228: left of '.fail' must have class/struct/union === stupid corporate footer=== TradeStation Group, Inc. is a publicly-traded holding company (NASDAQ GS: TRAD) of three operating subsidiaries, TradeStation Securities, Inc. (Member NYSE, FINRA, SIPC and NFA), TradeStation Technologies, Inc., a trading software and subscription company, and TradeStation Europe Limited, a United Kingdom, FSA-authorized introducing brokerage firm. None of these companies provides trading or investment advice, recommendations or endorsements of any kind. The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from any computer.

Sorry, that was my mistake. Version 2 has the space problem in 1.43, but not in 1.44. Version 3 is introduced in 1.44 but works in a different way and has the space problem. I don't know how well it (or lexical cast) handles L-strings. I've brought up the space issue on the development list, but I'm having a bit of trouble explaining it. Until a conclusion is reached, I'd suggest using strings in program options, and then constructing the filesystem path yourself.

Daniel

Food for the thought for the developers: In general, it would be confusing for lexical cast to do something different than a static cast, i.e. the constructor that takes a string as an argument. (In those cases where the ctor is indeed "converting" the string. When such a ctor form does something different, it makes sense that the lexical cast would be totally different.) Thanks, --John TradeStation Group, Inc. is a publicly-traded holding company (NASDAQ GS: TRAD) of three operating subsidiaries, TradeStation Securities, Inc. (Member NYSE, FINRA, SIPC and NFA), TradeStation Technologies, Inc., a trading software and subscription company, and TradeStation Europe Limited, a United Kingdom, FSA-authorized introducing brokerage firm. None of these companies provides trading or investment advice, recommendations or endorsements of any kind. The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from any computer.