Re: [PATCH] diff: "S_IFREG | 0644" to "(S_IFREG | 0644)" to avoid warning

From: Jonathan Nieder <jrnieder@gmail.com>
Date: Oct 4, 2010, 09:35 UTC
Message-ID: <20101004093519.GN24884@burratino>
In-Reply-To: <1286184071-28457-1-git-send-email-avarab@gmail.com>

Ævar Arnfjörð Bjarmason wrote:

> -	unsigned mode = canon_mode(S_IFREG | 0644);
> +	unsigned mode = canon_mode((S_IFREG | 0644));

Just curious:

#define canon_mode(mode) \
        (S_ISREG(mode) ? (S_IFREG | ce_permissions(mode)) : \
        S_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. How are they defined in NetBSD sys/stat.h? What is canon_mode(S_IFREG | 0644) being misinterpreted to mean?