D's are fairly similar to C's bitfields. They're more portable though as far as I know because you can specify the endianness as opposed to C which uses the pla

D's are fairly similar to C's bitfields. They're more portable though as far as I know because you can specify the endianness as opposed to C which uses the platform's endianness. Which from what I remember is the main reason C's bitfields are a poor choice for things. Any code isn't portable to architectures with a different endianness.