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Date:	Fri, 1 Jan 2010 16:37:32 +0000
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Subject:	Re: gcc4[1.7] printf treats differently a string constant and a character array
From:	Andy Koppe <andy DOT koppe AT gmail DOT com>
To:	rodmedina AT cantv DOT net, cygwin AT cygwin DOT com
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> Some comments:
> 1- I think that printf(string_constant) and printf(char_array) should give
> the same
> output in any circumstance.
> 2- In absence of a call to setlocale printf((string_constant) writes
> according to
> the locale of the environment, but =C2=A0printf(char_array) =C2=A0does no=
t, even
> though =C2=A0it is
> =C2=A0affected by the locale of the environment.

No, both work according to the "C" locale, with its UTF-8 character
set, and behaviour for invalid UTF-8 sequences is undefined for both.
"Undefined" means anything might happen, including inconsistent
behaviour. (Requiring consistent behaviour would make the puts
optimisation impossible.)

> 3- I think that a program that was written for locale=3DC should work wit=
hout
> modification
> if the locale in the environment is any of the one-byte characters ones.
> 4- I think that a plain C (8-bit transparent) locale should be available,
> even if it
> is not the default one.

If you don't call setlocale, all you can expect according to the C and
POSIX standards is the so-called portable character set. So you
shouldn't assume that the C locale is 8-bit transparent.

However, since that is a valid assumption on Linux and others, Cygwin
might indeed be better off following their example. There's a
discussion about that on cygwin-developers.

Andy

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