On Mon, Jan 04, 2010 at 03:32:07PM -0800, Bruce Blinn wrote: > > -----Original Message----- > > From: [email protected] > > [mailto:[email protected]] On Behalf Of Greg KH > > Sent: Sunday, January 03, 2010 1:27 PM > > To: Shawn > > Cc: [email protected] > > Subject: Re: question about __v annotation > > > > > > On Sat, Jan 02, 2010 at 09:10:08PM +0800, Shawn wrote: > > > hello guys, > > > I got a newbie confused when I was looking into the source code of > > > s3c2440's RTC driver.I dont know what is __v excatly > > means.anyone can > > > tell?thanks anyway! > > > > > > #define readb(c) ({ __u8 __v = __raw_readb(__mem_pci(c)); __v; }) > > > > __v is an variable that the macro creates and then returns > > the value of. > > > > Don't code like this, it's horrible :) > > > > Could you be more specific with what you find wrong with this. The reason I > ask is there is code like this all over the kernel.
Like what specifically? Wrapping up a function call in a macro just because someone doesn't want to type the whole thing out? That's the horrible thing. Returning a temporary variable isn't a big deal, but an inline function is better to use as you will get the proper type safety. thanks, greg k-h -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to [email protected] Please read the FAQ at http://kernelnewbies.org/FAQ
