[sdiy] Quick C query

[Scott Gravenhorst]

Tom Wiltshire <tom at electricdruid.net> wrote:
>
>On 21 Nov 2010, at 18:05, Steff wrote:
>
>> On 21 November 2010 17:45, cheater cheater <cheater00 at gmail.com> wrote:
>>> 
>>>> if(flags == (BLARP | BAR)) { /* do stuff here */ }
>>> 
>>> I think you mean:
>>> 
>>> if(flags & (A | B) == (A | B)) {
>>>  ...
>>> }
>
>I've seen this written as:
>
>	if (flags & (A | B)) {
>	 ...
>	}
>
>Which would be the following for a single flag:
>
>	if (flags & mask) {
>	 ...
>	}
>
>There's no need for the part with the "==(etc)", since C is just 
>looking for a non-zero result to indicate true (simply processor 
>zero flag clear, I hope). 
>
>Or have I got the stick by the sticky end?

Looks correct to me.  I use that kind of structure regulary in C (that is, "if"
statements without any comparison operator).

-- ScottG
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-- Scott Gravenhorst
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