Re: [RFC/PATCH 1/8] compat: provide a fallback va_copy definition

From: Jonathan Nieder <jrnieder@gmail.com>
Date: Feb 24, 2011, 20:33 UTC
Message-ID: <20110224203317.GC17412@elie>
In-Reply-To: <20110224142647.GA15477@sigill.intra.peff.net>

Jeff King wrote:

> So my guess is that this will be sufficient, but I we won't really know
> for sure until somebody reports a problem. :(

Sounds like a good approach to me.

The POSIX rationale hints that some historical implementations used arrays of size 1. Assignment would error out on such an implementation, which is not a big deal (since we could switch to memcpy then). I would be more worried about a historical implementation using dynamic allocation with va_list being a pointer but I haven't heard of any.

> +#ifndef va_copy
> +#define va_copy(dst,src) (dst) = (src)
> +#endif

The following (as Erik mentinoed) might be a nice cleanup on top. The duplicate va_copy definition is just redundant rather than causing compilation errors because it comes before git-compat-util's ifndef-guarded one.

diff --git a/compat/msvc.h b/compat/msvc.h
index 023aba0..a33b01c 100644
--- a/compat/msvc.h
+++ b/compat/msvc.h
@@ -9,7 +9,6 @@
 #define inline __inline
 #define __inline__ __inline
 #define __attribute__(x)
-#define va_copy(dst, src)     ((dst) = (src))
 #define strncasecmp  _strnicmp
 #define ftruncate    _chsize