Re: [Boost-users] [crc] why static data members used in class?

Subject: Re: [Boost-users] [crc] why static data members used in class?
From: John Maddock (jz.maddock_at_[hidden])
Date: 2015-07-09 13:24:45

> I don't understand why the author has used static data members in the 
> class below.
> Isn't that an indication that this class cannot be used in a 
> multithreaded environment?
>
> class boost::crc_optimal
> {
> public:
>     // Type
>     typedef implementation_defined  value_type;
>
>     // Constants reflecting template parameters
>     static  std::size_t const  bit_count = Bits;
>     static  value_type const   truncated_polynominal = TruncPoly;
>     static  value_type const   initial_remainder = InitRem;
>     static  value_type const   final_xor_value = FinalXor;
>     static  bool const         reflect_input = ReflectIn;
>     static  bool const         reflect_remainder = ReflectRem;

static const integer types are all compile-time constants - they're just 
fine in a multithreaded environment - and IMO this is the correct way to 
define constants that are known at compile time (albeit C++11 adds 
constexpr, but it doesn't really change anything in this use case).

HTH, John.