This appears not to have made it into 1.71.0. I had to edit crc.hpp:569 to silence the warning. --On Saturday, April 13, 2019 1:35 PM -0700 Kenneth Porter via Boost wrote:

https://github.com/boostorg/crc/pull/2

Visual Studio 2010-2019 issue this warning for crc.hpp line 569:

warning C4800: "'int' : forcing value to bool 'true' or 'false' (performance warning)

bool const quotient = remainder & high_bit_mask;

Replace with:

bool const quotient = (remainder & high_bit_mask) != 0;