Re: [RFA] Fix typo in type of parameter "w" in print_wchar...

[Mark Kettenis <mark.kettenis@xs4all.nl>]

> Date: Fri, 24 Apr 2009 17:36:58 -0700
> From: Joel Brobecker <brobecker@adacore.com>
> 
> I think this is the last issue I've found so far with character set
> conversions and printing...
> 
> This one occurs on AIX while trying to print a simple ascii string.
> The output looks like this:
> 
>     (gdb) p __gnat_version 
>     $3 = "
> 
> The problem turned out to be pretty straightforward, once I got to
> understand how things are supposed to work.
> 
> Basically, for every character in our string, we call print_wchar
> to push the equivalent wchar on our itermediate wchar buffer.
> The issue is that we had the wrong type for the wchar (gdb_wint_t
> instead of gdb_wchar_t). gdb_wint_t is 4bytes long whereas gdb_wchar_t
> is 2 bytes long. So when we do the pushing:
> 
>       obstack_grow (output, &w, sizeof (gdb_wchar_t));
> 
> We only push 2 bytes of the 4 bytes that w got accidently promoted to.
> On ppc-aix, it's big endian, so we end up always pushing zeros...
> 
> 2009-04-24  Joel Brobecker  <brobecker@adacore.com>
> 
>         * c-lang.c (print_wchar): Use the correct type for parameter "w".
> 
> I'm currently testing the patch on x86_64-linux...

I think this is wrong.  The type of a single wide character is wint_t
instead of wchar_t such that it can properly hold WEOF, much in the
same way as the "normal" character functions use int instead of char.

The proper/safer approach is probably to do the conversion to wchar_t
in print_wchar itself just before that obstack_grow() call.

> diff --git a/gdb/c-lang.c b/gdb/c-lang.c
> index 027e9b2..5fe04de 100644
> --- a/gdb/c-lang.c
> +++ b/gdb/c-lang.c
> @@ -156,7 +156,7 @@ append_string_as_wide (const char *string, struct obstack *output)
>     escapes across calls.  */
>  
>  static void
> -print_wchar (gdb_wint_t w, const gdb_byte *orig, int orig_len,
> +print_wchar (gdb_wchar_t w, const gdb_byte *orig, int orig_len,
>  	     int width, struct obstack *output, int quoter,
>  	     int *need_escapep)
>  {