Re: [PATCH v1 1/2] vsprintf: introduce %dE for error constants

[Jani Nikula]

On Mon, 26 Aug 2019, Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx> wrote:
> On Sat, 24 Aug 2019, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
>>> --- a/lib/vsprintf.c
>>> +++ b/lib/vsprintf.c
>>> @@ -533,6 +533,192 @@ char *number(char *buf, char *end, unsigned long long num,
>>>  	return buf;
>>>  }
>>>  
>>> +#define ERRORCODE(x) { .str = #x, .err = x }
>>> +
>>> +static const struct {
>>> +	const char *str;
>>> +	int err;
>>> +} errorcodes[] = {
>>
>> It's a bit of a hack, but an array of char*'s and a separate array of
>> ushorts would save a bit of space.
>
> Or just
>
> #define ERRORCODE(x) [x] = #x
>
> static const char * const errorcodes[] = {
> 	ERRORCODE(EPERM),
>         ERRORCODE(ENOENT),
>         ...
> };
>
> Saves space, faster lookup, discovers at build time why EWOULDBLOCK
> would always show up as EAGAIN in the logs. We don't have holes to speak
> of in the error codes.

Meh, failed to notice the range ERESTARTSYS..ERECALLCONFLICT. Other than
that, it's nicer. ;)

BR,
Jani.

-- 
Jani Nikula, Intel Open Source Graphics Center