On 02/11/2011 21:35, Max Bolingbroke wrote:
On 2 November 2011 10:32, Simon Peyton-Jones<[email protected]> wrote:
Unicode stuff (I assume)
lib/IO 3307 [bad exit code] (normal)
lib/IO environment001 [bad stdout] (normal)
I've never been able to reproduce this with Cygwin, but I rebuilt GHC
on msys and managed to find out what is going on. Basically, msys has
kind of bad Unicode support. If you write a program "len.c" like this:
"""
#include<windows.h>
#include<stdio.h>
#include<string.h>
int main(int _argc, char **_argv) {
LPWSTR cmdLine = GetCommandLineW();
int argc;
LPWSTR *argv = CommandLineToArgvW(cmdLine,&argc);
printf("%d args, %d wide chars in first arg\n", argc, wcslen(argv[1]));
return 0;
}
"""
Create a UTF-8 encoded file called "utf8" containing two characters:
"""
不好
"""
And then execute it like so:
"""
gcc len.c&& ./a.exe $(cat utf8)
"""
(NB: it is irrelevant whether you use Cygwin gcc or msys gcc: this is
an issue with the *shells*)
You get different results on msys and Cygwin:
* On Cygwin, you get 2 wide characters in the first argument -- i.e.
the UTF-16 encoded Chinese text
* On msys, you get 6 wide characters in the first argument -- i.e.
one 16-byte value for *every byte* in the UTF-8 encoded Chinese text
IMHO the msys behaviour is broken because the command line arguments
supplied via the Windows API are meant to be UTF-16. It *does* match
the behaviour of Windows cmd if you do this:
"""
set /p myvar=< utf8
a.exe %myvar%
"""
(You get "6 wide characters" printed)
Perhaps the issue in cmd stems from the fact that the Windows console
is stuck in code page 850 and doesn't support the UTF-8 "code page".
But msys really has no excuse since it reports itself as being UTF-8.
I'm not sure what to do here because I don't think our code actually
has a problem, and the test does pass (and check something useful) in
Linux, OS X and Cygwin. But still, something is not working quite
right here. Perhaps just mark it as expect-fail in msys?
Nice diagnosis - I've been meaning to get to the bottom of this one for
ages. Expect-fail on MSYS seems like the right thing to me.
Cheers,
Simon
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