Thanks for the review.  A new revision is attached.

On 6/6/22 06:59, Eli Zaretskii wrote:
> I think it is better to say
> 
>    Unibyte string that is @var{len} bytes long.

Done.  I may have gone overboard though -- I did so because there are three representations that matter:

   1. The input string to be packed.
   2. The packed output.
   3. The result of unpacking.

Right now all three of those are unibyte, but in a future patch I plan on changing the first to accept unibyte-convertible multibyte input strings.

> Our conventions are to leave two spaces between sentences.

Done.

> Also, for consistency, I suggest to use "null byte" everywhere, to 
> avoid potential confusion of non-native English speakers.

Done.

I also fixed a flaw in the previous revision: packing to a fixed-length field doesn't actually write a null byte if the input is shorter than the field. This only matters if the caller provided a pre-allocated string that doesn't have null bytes.

Thanks,
Richard