[Boost-users] [filesystem] Should fstream really 'force' in+out mode?

I want to open a read only file in ios::in mode using fstream but its open forces in+out mode, causing my open to fail when it could have succeeded. In boost::filesystem::fstream::open, the file open mode is modified to mode | std::ios_base::in | std::ios_base::out Is this really necessary or can this be changed in future? Atleast with MSVC 9.0, std::fstream isn't forcing such behavior. SG