From mboxrd@z Thu Jan  1 00:00:00 1970
From: Al Viro <viro@ftp.linux.org.uk>
Subject: Re: [PATCH] Fix compilation warning on 64 bits platforms
Date: Mon, 21 May 2007 01:33:18 +0100
Message-ID: <20070521003318.GB4095@ftp.linux.org.uk>
References: <11797058752907-git-send-email-damien.lespiau@gmail.com> <4650E7B5.4030207@freedesktop.org>
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To: Josh Triplett <josh@freedesktop.org>
Cc: Damien Lespiau <damien.lespiau@gmail.com>, linux-sparse@vger.kernel.org

On Sun, May 20, 2007 at 05:28:37PM -0700, Josh Triplett wrote:
> Damien Lespiau wrote:
> > Fix: format '%d' expects type 'int', but argument 2 has type 'long int'
> [...]
> > @@ -461,7 +461,7 @@ const char *show_instruction(struct instruction *insn)
> >  	}
> >  
> >  	if (buf >= buffer + sizeof(buffer))
> > -		die("instruction buffer overflowed %d\n", buf - buffer);
> > +		die("instruction buffer overflowed %d\n", (int)(buf - buffer));
> 
> A cast doesn't seem like the right fix.  The difference between two pointers
> has type ptrdiff_t.  sizeof(ptrdiff_t) == 8 on 64-bit platforms, leading to
> the legitimate warning you saw.  This cast would truncate the difference to 32
> bits.  glibc supplies a "t" length modifier for ptrdiff_t, but I don't think
> sparse can't portably use that.

Not just glibc; it's in C99.  So yes, I'd say we should use %td here.