From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anton Vorontsov Date: Tue, 1 Sep 2009 22:25:18 +0400 Subject: [U-Boot] [PATCH 1/2] Move uninitialized_var() macro from ubi_uboot.h to compiler.h In-Reply-To: <20090901181141.2D46F834A950@gemini.denx.de> References: <20090901165803.GA3668@oksana.dev.rtsoft.ru> <20090901181141.2D46F834A950@gemini.denx.de> Message-ID: <20090901182518.GA17903@oksana.dev.rtsoft.ru> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Tue, Sep 01, 2009 at 08:11:41PM +0200, Wolfgang Denk wrote: > Dear Anton Vorontsov, > > In message <20090901165803.GA3668@oksana.dev.rtsoft.ru> you wrote: > > This is needed so that we could use this macro for non-UBI code. > > > > Signed-off-by: Anton Vorontsov > > --- > > include/compiler.h | 3 +++ > > include/ubi_uboot.h | 4 +--- > > 2 files changed, 4 insertions(+), 3 deletions(-) > > > > diff --git a/include/compiler.h b/include/compiler.h > > index 272fd3c..e602cce 100644 > > --- a/include/compiler.h > > +++ b/include/compiler.h > > @@ -122,4 +122,7 @@ typedef unsigned int uintptr_t; > > > > #endif > > > > +/* compiler options */ > > +#define uninitialized_var(x) x = x > > Please excuse my ignorance, but where and what for is such a > definition useful? It's used to avoid GCC warnings, i.e. when GCC isn't smart enough to see that some variable isn't actually used uninitialized. ~/linux-2.6$ git grep uninitialized_var drivers/ | wc -l 94 We can fix the warnings by assigning some value to a variable at declaration, but the advantage of 'x = x' trick is that it doesn't generate any code. Thanks, -- Anton Vorontsov email: cbouatmailru at gmail.com irc://irc.freenode.net/bd2