Language Reference, updated

[Mike Mason]

Frank Ch. Eigler wrote:
>>     MM> Section 3.6 Mention use of the deref() macro in embedded C for
>>     MM> safety.  Give an example.
>>
>> I could use a little help with this. Would anyone be able to provide a
>> good working example?
> 
> There are examples in the tapset.  Josh switched us over to the
> "kread" function:
> 
> function _struct_timeval:string(addr:long)
> %{ /* pure */
>         struct timeval *tv = (struct timeval *)(unsigned long)THIS->addr;
> 
>         if (tv == NULL)
>                 strlcpy (THIS->__retvalue, "NULL", MAXSTRINGLEN);
>         else
>                 snprintf(THIS->__retvalue, MAXSTRINGLEN, "[%ld.%06ld]",
>                                 kread(&(tv->tv_sec)), kread(&(tv->tv_usec)));
> %}
> 
> (However, it is not clear that the NULL-handling case is relevant or
> appropriate.  If the timeval* coming in from the application is
> permitted to be NULL, fine, but if it's meant as a crash-prevention
> mechanism in this embedded-C routine, then it's not right.)

What's the right thing to do if NULL isn't permitted?  Should we let kread() report the error or do something else?

Thanks,
Mike