Re: [Xen-devel] [PATCH] cmdline: treat hyphens and underscores the same

[Jan Beulich <jbeulich@xxxxxxxx>]

On 06.12.2019 17:20, Julien Grall wrote:
> Hi,
> 
> On 06/12/2019 16:06, Jan Beulich wrote:
>> On 06.12.2019 15:46, Julien Grall wrote:
>>> On 05/12/2019 16:50, Jan Beulich wrote:
>>>> On 05.12.2019 17:27, Julien Grall wrote:
>>>>> On 05/12/2019 15:33, Jan Beulich wrote:
>>>>>> +/*
>>>>>> + * String comparison functions mostly matching strcmp() / strncmp(),
>>>>>> + * except that they treat '-' and '_' as matching one another.
>>>>>> + */
>>>>>> +static int _strcmp(const char *s1, const char *s2)
>>>>>
>>>>> I thought we were trying to avoid new function name with leading _?
>>>>
>>>> We're trying to avoid new name space violations. Such are
>>>> - identifiers starting with two underscores,
>>>> - identifiers starting with an underscore and an upper case letter,
>>>> - identifiers of non-static symbols starting with an underscore.
>>>
>>> I am not sure to understand why non-static symbols only. This would
>>> prevent you to use the the non-static symbol if you happen to re-use the
>>> same name.
>>
>> I'm afraid I don't understand. Anyway - what I've listed above is
>> what the language standard mandates.
> AFAIU, for a given unit, there is only one pool of identifiers. So you 
> could not have an identifier used at the same time by a non-static and a 
> static symbol (that's exclusing the weak attribute). So it feels 
> slightly strange to only cover the non-static symbols.

I guess I'm still not getting your point. What the above tells
us is that static symbols may start with an underscore (but
not followed by another one or an uppercase letter). Non-static
symbols may not.

>>> Anyway, how about calling it cmdline_strncmp()? This would be easier to
>>> spot misuse on review (i.e using strncmp() rather than _strncmp()).
>>
>> We already have cmdline_strcmp(), or else I would indeed have used
>> this prefix. No prefix (other than the lone underscore) seemed the
>> next best option.
> 
> As we parse an option, how about opt_strncmp()?

I'd still like _strncmp() better here.

Jan

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