[alsa-devel] [PATCH V4 1/5] The macro spin_event_timeout() takes a condition and timeout value

[Geert Uytterhoeven]

On Tue, 26 May 2009, Timur Tabi wrote:
> On Tue, May 26, 2009 at 2:29 AM, Geert Uytterhoeven
> <Geert.Uytterhoeven at sonycom.com> wrote:
> 
> > static inline function, returning rc, instead of a macro?
> 
> It won't work as an inline function ...
> 
> >> +     unsigned long __loops = tb_ticks_per_usec * timeout;                \
> >> +     unsigned long __start = get_tbl();                                  \
> >> +     while ((rc = (condition)) && (tb_ticks_since(__start) <= __loops)) \
> 
> There's no way to pass a expression to an inline function.  It has to
> be a macro.  Here, the loop evaluates "condition" at every pass.  If
> this were an inline function, "condition" would be evaluated once when
> the function were called, and never again.

You're right, I missed that part. Sorry about that.

However, you can still improve useability by making the macro return the rc,
instead of letting the caller pass it, cfr. wait_event_timeout() and friends.

With kind regards,

Geert Uytterhoeven
Software Architect
Techsoft Centre

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