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Re: Simple(?) Unicode questions

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Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:

> Tim Rentsch <tr.17687@z991.linuxsc.com> writes:
>
>> Lew Pitcher <lew.pitcher@digitalfreehold.ca> writes:
>>
>>> On Wed, 13 Dec 2023 11:05:45 +0800, spender wrote:
>>>
>>>> printf("%c",ch), the ch must <0xFF, <255
>>>
>>> Not quite.
>>> 1) ch /must/ represent an integer value.
>>
>> More specifically, it must have a type that is or promotes
>> to int, or a type that is or promotes to unsigned int, with
>> a value that is in the common range of int and unsigned int.
>
> Not quite.  "If no l length modifier is present, the int argument
> is converted to an unsigned char, and the resulting character is
> written."  For example printf("%c", -193) is equivalent to
> printf("%c", 63), which assuming an ASCII-based character set will
> print '?'.

The rule for arguments to printf() is the same as the rule for
accessing variadic arguments using va_arg().  That has always
been true, although not expressed clearly in early versions of
the C standard.  Fortunately that shortcoming is addressed in
the upcoming C23 (is it still not yet ratified?):  in N3096,
paragraph 9 in section 7.23.6.1 says in part

    fprintf shall behave as if it uses va_arg with a type
    argument naming the type resulting from applying the
    default argument promotions to the type corresponding
    to the conversion specification [...]

and the rule for va_arg (in 7.16.1.1 p2) says in part 

    one type is a signed integer type, the other type is
    the corresponding unsigned integer type, and the value
    is representable in both types

So supplying an unsigned int argument is okay, provided of
course the value is in the range of values of signed int.

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Re: Simple(?) Unicode questions Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2023-12-13 14:56 +0000
  Re: Simple(?) Unicode questions Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-12-25 02:03 -0800
    Re: Simple(?) Unicode questions Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-12-25 14:43 -0800
      Re: Simple(?) Unicode questions Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-01-20 09:33 -0800
        Re: Simple(?) Unicode questions Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-01-20 14:19 -0800
          Re: Simple(?) Unicode questions Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-01-24 20:38 -0800

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