[PATCH xf86-input-synaptics 07/10] Add touch valuator mask to hw state structure

[walter harms]

Am 09.02.2012 18:22, schrieb Chase Douglas:
> On 02/09/2012 03:27 PM, Peter Hutterer wrote:
>> On Wed, Feb 08, 2012 at 06:35:16PM -0800, Chase Douglas wrote:
>>> Signed-off-by: Chase Douglas <chase.douglas at canonical.com>
>>> ---
>>>  src/synaptics.c    |   78 ++++++++++++++++++++++++++++++++++++++++++++++++++-
>>>  src/synapticsstr.h |    1 +
>>>  src/synproto.h     |    5 +++
>>>  3 files changed, 82 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/src/synaptics.c b/src/synaptics.c
>>> index c0398fb..b01be59 100644
>>> --- a/src/synaptics.c
>>> +++ b/src/synaptics.c
>>> @@ -1151,6 +1151,8 @@ DeviceInit(DeviceIntPtr dev)
>>>  #ifdef HAVE_MULTITOUCH
>>>      if (priv->has_touch)
>>>      {
>>> +        priv->num_slots = priv->max_touches ? : 10;
>>
>> whoah, didn't know that was legal. is this gcc or std C?
>> either way, I'd rather not do that because of this behaviour:
>>
>>     int a = 12;
>>     a = (a > 10) ? : 10;
>>     → a is now 1
>>     
>> Not quite what one would expect.
> 
> I think it is standard C. It's not seen too often because many times
> you're checking a value against something non-zero. A better example of
> how not to do it is:
> 
> a = (b > 0) ? : 10;
> 
> I don't see any reason why what I have is bad, but I'll change it if it
> makes you cringe. People writing C need to know what they are doing, and
> this isn't one of those areas where what really happens is different
> than what one might think.
> 


IMHO this is a gcc extension. (Conditionals with omitted Operands)
 a = (b > 0) ? : 10; is equal to
 a = (b > 0) ? (b > 0) : 10;


re,
 wh