Hi Seth,

On Tue, Jan 06, 2026 at 05:08:01PM +1000, Seth McDonald wrote:
> pid_t(3type), uid_t(3type), and gid_t(3type) were initially not
> specified as integer types, but as arithmetic types:
> 
> "All of the types listed in Table 2-1 shall be arithmetic types; pid_t
> shall be a signed arithmetic type."[1]
> 
> This technically means the types could be floating-point arithmetic
> types in systems conforming to early versions of POSIX.1.

But did any implementations do this?  As far as I know, there were none,
which turns this into something that was only true in paper, and can be
entirely ignored.


Cheers,
Alex

> [1] IEEE Std 1003.1-1988, Section 2.6 "Primitive System Data Types".
> 
> Signed-off-by: Seth McDonald <sethmcmail@pm.me>
> ---
>  man/man3type/id_t.3type | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/man/man3type/id_t.3type b/man/man3type/id_t.3type
> index c4b87642c755..ad79394b1b72 100644
> --- a/man/man3type/id_t.3type
> +++ b/man/man3type/id_t.3type
> @@ -50,6 +50,15 @@ .SH HISTORY
>  .TP
>  .I id_t
>  POSIX.1-2001.
> +.P
> +Initially, POSIX.1-1988 only specified
> +.IR pid_t ,
> +.IR uid_t ,
> +and
> +.IR gid_t
> +as arithmetic types.
> +It was from POSIX.1-2001
> +that they were restricted to integer types.
>  .SH NOTES
>  The following headers also provide
>  .IR pid_t :
> -- 
> 2.47.3
> 
> 

-- 
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