[PATCH 4/4] winmm: Fix check for DCB_NULL callback type

Andrew Eikum wrote:
> - if(info->flags & DCB_NULL)
> - if((info->flags & DCB_TYPEMASK) == DCB_NULL)

Instead of add ing a special case, I suggest to simplify the code: always call DriverCallback and declare
void WINMM_NotifyClient. You currently ignore its return value anyway.
Using void is consistent with an ealier notification patch of mine around April this year.

Michael,
wouldn't it be possible to add a function to the static checkers to be able
to detect static functions whose return is systematically ignored and rewrit these  and their callers to use void?
I came across another occurence of that pattern no later than yesterday (mcimidi IIRC).

Regards,
 Jörg Höhle

[Michael Stefaniuc]

Hello Jörg,

On 07/20/2011 02:28 PM, [e-mail] wrote:
> wouldn't it be possible to add a function to the static checkers to be able
> to detect static functions whose return is systematically ignored and rewrit these  and their callers to use void?
> I came across another occurence of that pattern no later than yesterday (mcimidi IIRC).

that can be done in theory with coccinelle. The devil is in the
implementation details. The basic idea is simple (think set operations).
rule1: Find all the function calls in the file that use the return value
rule2: Find the static function declaration/definitions and happen to
have a function name found in rule1. Mark them as good.
rule3: Change the return type of all the other static functions to void.
The callers of those functions need no change; they ignore the return
value anyway.

Of course the above rules can expand to multiple real coccinelle rules
and multiple alternations. Especially finding the "return value is used"
case will require a few different matches.

I'll have a go at it but I can't promise as I'm freaking busy lately.

bye
    michael