<AWT Dev> [9] Review request: new macro for conversion to jboolean

Anthony Petrov anthony.petrov at oracle.com
Mon Mar 24 11:11:16 UTC 2014

How does IS_JNI_TRUE sound?

best regards,

On 3/23/2014 10:10 PM, Alan Bateman wrote:
> On 21/03/2014 15:22, Sergey Bylokhov wrote:
>> On 3/21/14 7:10 PM, roger riggs wrote:
>>> The macro would just as useful (if I understand the cases) without
>>> the cast.
>>> How useful is a simple definition as:
>>> #define IS_TRUE(obj) ((obj) ? JNI_TRUE : JNI_FALSE)
>>> then it would look ok to see these in sources:
>>>       return IS_TRUE(obj);
>>>       if (IS_TRUE(obj)) {....}
>>>       jboolean ret = IS_TRUE(obj);
>>> The general purpose usage matches the general C conventions for
>>> true and false and match the JNI semantics.
>> Actually that was my initial suggestion(name and usage).
> I think the concern with IS_TRUE is that it's not obvious that it's a
> jboolean. Also just the potential for it to easily collide with a macro
> that casts to bool or (or Windows's BOOL). I can't tell from the JNI
> spec if JNI_FALSE/JNI_TRUE are guaranteed to be defined as 0/1 but even
> if they are then I guess there is still a concern that a jboolean is
> defined as an unsigned 8 bits whereas a bool might not (and a Windows's
> BOOL is an int I think). So if a macro is really needed then I think it
> will need another name. I thought MIke's original proposal for
> JNU_TO_JBOOLEAN wasn't too bad. I see Mike's mail about adding the cases
> to the definitions but that isn't going to help with the cases that I
> think you are running into where you need to go from Window's BOOL to
> jboolean.
> -Alan.

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