Re: [boost] [gil] gcc fail with simple code

28 Mar 2018


      On 28 March 2018 at 21:23, Andrey Semashev via Boost
 wrote:
...
On 03/28/18 22:10, Stefan Seefeld via Boost wrote:
...
On 28.03.2018 14:48, Christian Henning via Boost wrote:
...
...
I would suggest casting to unsigned first and then performing the math.
I assume this is what you meant:
template <> struct channel_convert_to_unsigned<bits32s> : public
std::unary_function {
     typedef bits32 type;
     type operator()(bits32s x) const
     {
         uint32_t a = static_cast(x);
         a += (1 << 31);
return static_cast<bits32>(a);
     }
};
Or simply replace `static_cast<bits32>(x+(1<<31))` by
`static_cast<bits32>(x)+(1<<31)` (i.e., cast `x` rather than the full
expression).
Rather:
static_cast<bits32>(x)+(static_cast<bits32>(1)<<31)
to make it compatible with older C++ versions.
I think Andrey's version also sticks out and documents the danger better,
than 'cosmetic' shuffle of one bracket.

Best regards,
-- 
Mateusz Loskot, http://mateusz.loskot.net