Re: [dev] [st] wide characters

From: <random832_AT_fastmail.us>
Date: Mon, 15 Apr 2013 15:47:24 -0400

On Mon, Apr 15, 2013, at 15:36, Thorsten Glaser wrote:
> Actually, wint_t is the standard type to use for this. One
> could also use wchar_t but that may be an unsigned short on
> some systems, or a signed or unsigned int.

Those systems aren't using wchar_t *or* wint_t for unicode, though.

The main reason for wint_t's existence is that wchar_t isn't guaranteed
to be able to represent a WEOF value distinct from all valid character
values. wchar_t can be used just fine for any actual character, but if
the system doesn't use unicode as its wchar type, it could (for example)
be a signed 16-bit int to wchar_t's unsigned 8-bit.

You can use #if __STDC_ISO_10646__ to test whether the implementation
uses unicode for wchar_t (most modern systems do, though some may not
define this constant) - if so, then wchar_t is, naturally, guaranteed to
be able to represent at least the range 0 to 0x10FFFF, and wint_t that
plus WEOF (usually -1). They're usually both 32-bit signed ints.

MS Windows uses an unsigned short for both types due to various
historical reasons.
Received on Mon Apr 15 2013 - 21:47:24 CEST