Linux and the 'clssic' computing world

Paul Koning paulkoning at
Tue Sep 28 13:14:52 CDT 2021

> On Sep 28, 2021, at 1:43 PM, Vincent Slyngstad via cctalk <cctalk at> wrote:
> On 9/28/2021 5:14 AM, Toby Thain via cctalk wrote:
>> On 2021-09-27 11:46 p.m., ben via cctalk wrote:
>>> POSIX requires a byte to be exactly 8 bits I read somewhere.
>>> C99 C standard?
>>> Great for ARM and INTEL, not so great for the 36 bit computers.
>> We've been through this before. No.
> As I understand things, POSIX does require the existence of 8 bit bytes, (int8_t and uint8_t) and requires them to be exactly 8 bits.  It does not AFAIK explicitly prohibit the existence of bytes with other sizes, but who would bother?
> The C standards are more liberal, and continue to require char types to be 8 or more bits.

You're mixing up two unrelated things.  int8_t is an integer type of 8 bits width.  char is the type used for characters.  While in many machines they are the same size, that isn't required.

C compilers have been built for machines with non-8 bit characters, from the CDC 6600 to the PDP-10 and Cray-1 and various DSPs.  GCC at one time (some of them still, I think) handled all these except the 6600.


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