Re: [PATCH v4] Add utf8_fprintf helper which returns correct columns

["Torsten Bögershausen" <tboegi@web.de>]

On 08.02.13 08:20, Jiang Xin wrote:
> 2013/2/8 Torsten Bögershausen <tboegi@web.de>:
>> On 08.02.13 03:10, Jiang Xin wrote:
>>> +     /* If no error occurs, returns columns really required with utf8_strwidth. */
>>> +     if (0 <= columns)
>>> +             columns = utf8_strwidth(buf.buf);
>>> +     strbuf_release(&buf);
>>> +     return columns;
>>> +}
>>> +
>>
>> I don't think we handle the return code from fputs() correctly.
>>
>> Please dee below for specifications on fprintf(),
>> something like the following could do:
>>
>> int utf8_fprintf(FILE *stream, const char *format, ...)
>> {
>>         struct strbuf buf = STRBUF_INIT;
>>         va_list arg;
>>         int columns = 0;
>>
>>         va_start (arg, format);
>>         strbuf_vaddf(&buf, format, arg);
>>         va_end (arg);
>>
>>         if (EOF != fputs(buf.buf, stream))
>>                 columns = utf8_strwidth(buf.buf);
>>         strbuf_release(&buf);
>>         return columns;
>> }
> 
> As fputs() returns a non-negative number (as opposed to 0) on
> successful completion,
> Test fputs() return value as "fputs() >=0" is correct, while "fputs()
> == 0", "fputs() != 0"
> are wrong. I think it's OK, must I send a new re-roll for this?
> 
> EOF is defined as (-1) in stdio.h:
> 
>     #define EOF     (-1)
> 
>> And as a side note: would fprintf_strwidth() be a better name?
> 
> This is a nice candidate.
> 
> 

Doing a slurp(coffe) followed by a re-read,
I think we are save with the existng code.

However, I feel that the commit message can be improved, 
as it fixes problems not only for CJK but e.g. european languages
(and all systems using utf-8)

>Since command usages can be translated, they may not align well especially
>when they are translated to CJK. A wrapper utf8_fprintf can help to return
>the correct columns required.
 
Since command usages can be translated, they may include utf-8 encoded strings,
and strlen() is different from strwidth().
A wrapper utf8_fprintf() helps to return the correct columns required.


Thanks for working on this.