On Wed, Sep 02, 2009 at 05:11:12AM -0400, Mike Frysinger wrote:
> On Wed, Sep 2, 2009 at 04:57, Marc Andre Tanner wrote:
> > On Tue, Sep 01, 2009 at 07:37:27PM -0400, Mike Frysinger wrote:
> >> On Tue, Sep 1, 2009 at 18:31, Marc Andre Tanner wrote:
> >> > This series adds a configuration option to selectively compile out
> >> > printk message strings based on a verbosity level.
> >> >
> >> > This works by wrapping printk with a macro which evaluates to a
> >> > constant if condition which the compiler will be able to optimize
> >> > out.
> >> >
> >> > However because printk might be wrapped by a macro it no longer has
> >> > a return value. This means that constructs like the following ones
> >> > don't work:
> >> >
> >> > ((void)(SOME_RANDOM_DEBUG_FLAG && printk(...));
> >> >
> >> > some_random_variable = printk(...);
> >> >
> >> > Therefore printk_unfiltered is introduced which is just an alias
> >> > to the standard printk function but not wrapped by a macro.
> >>
> >> why dont you return 0 if it gets optimized away ? then you wont have
> >> to screw with external code at all and things "just work".
> >
> > This won't work because it would for example also return from functions
> > which call printk but aren't checking for the return value (which is
> > the common case).
>
> why would it matter ?
>
> ({
> int __printk_ret = 0;
> if (crazy stuff you're adding)
> __printk_ret = printk(.....);
> __printk_ret;
> })
Yes I missunderstood your "return 0" statement in the first mail.
The same effect could also be achieved by:
((crazy stuff) ? printk(...) : 0;
Marc
--
Marc Andre Tanner >< http://www.brain-dump.org/ >< GPG key: CF7D56C0
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