On Mon, Oct 4, 2010 at 09:35, Jonathan Nieder <jrnieder@xxxxxxxxx> wrote:
> Ãvar ArnfjÃrà Bjarmason wrote:
>
>> - Â Â unsigned mode = canon_mode(S_IFREG | 0644);
>> + Â Â unsigned mode = canon_mode((S_IFREG | 0644));
>
> Just curious:
>
> #define canon_mode(mode) \
> Â Â Â Â(S_ISREG(mode) ? (S_IFREG | ce_permissions(mode)) : \
> Â Â Â ÂS_ISLNK(mode) ? S_IFLNK : S_ISDIR(mode) ? S_IFDIR : S_IFGITLINK)
>
> #define ce_permissions(mode) (((mode) & 0100) ? 0755 : 0644)
>
> Since S_ISREG et al are macros, typically they would put their
> argument in parentheses in the definition. ÂHow are they defined
> in NetBSD sys/stat.h? ÂWhat is canon_mode(S_IFREG | 0644) being
> misinterpreted to mean?
Oh it's a bug in NetBSD, sorry for not being explicit about that:
$ grep S_ISREG /usr/include/sys/stat.h
#define S_ISREG(m) ((m & _S_IFMT) == _S_IFREG) /* regular file */
$ grep S_ISREG /usr/include/linux/stat.h
#define S_ISREG(m) (((m) & S_IFMT) == S_IFREG)
I.e. GCC sees `S_IFREG | 0644 & _S_IFMT' on NetBSD but `(S_IFREG |
0644) & _S_IFMT' on Linux.
Since bitwise AND (&) has precedence over bitwise OR it's probably a
logic error on NetBSD too, not just an annoying warning.
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