On 10/30/2015 06:10 PM, DJ Delorie wrote:
$subject as far as I am aware these are the same on all supported targets.The documentation for __CHAR_BIT__ says not to use it... @item __CHAR_BIT__ Defined to the number of bits used in the representation of the @code{char} data type. It exists to make the standard header given numerical limits work correctly. You should not use this macro directly; instead, include the appropriate headers.
I think that's for normal user code that's intended to be portable.
And the definition of BITS_PER_UNIT is more appropriate anyway: @item BITS_PER_UNIT The number of bits in an addressable storage unit (byte). If you do not define this, the default is 8. If a target had a sizeof(char) != 1, __CHAR_BIT__ and BITS_PER_UNIT would be different, and IMHO BITS_PER_UNIT is the one we want to use in the runtime, unless you're specifically talking about the "char" type:
sizeof char is defined to be 1, so I think for libgcc code __CHAR_BIT__ is probably usable and appropriate.
Bernd
