Re: [PATCH v2 7/7] misc: syslog: Use RFC5424

[Paul Eggert <eggert@cs.ucla.edu>]

There should be documentation about the change, somewhere.

On 2/18/22 06:23, Adhemerval Zanella via Libc-alpha wrote:

> +  struct tm *gmtm = __gmtime64_r (&ts.tv_sec, &now_tm);
> +  if (gmtm == NULL)
> +    strcpy (timebuf->b, NILVALUE);

RFC 5424 requires unsigned four-digit years, so change "gmtm == NULL" to 
"gmtm == NULL || ! (-1900 <= gmtm->tm_year && gmtm->tm_year <= 9999 - 
1900)". Or, if the idea is to depart from RFC 5424 for out-of-range 
years (which might be better), document the departure.

> +  else
> +    {
> +      size_t datebytes = __strftime_l (timebuf->b, sizeof timebuf->b,
> +				       "%FT%T", gmtm, _nl_C_locobj_ptr);
RFC 5424 does not allow leap seconds, so something like this:

     if (gmtm->tv_sec == 60)
       {
          gmtm->tv_sec = 59;
          gmtm->tv_nsec = 999999999;
       }

before calling __strftime_l. (Or again, if the idea is to depart from 
RFC 5424, document the departure.)

> +      int usec = ts.tv_nsec / 1000;

Typically fewer instructions (and still correct) if you replace 1000 
with 1000ul (admittedly a microoptimization....).