Array of booleans

[Maurizio Cimadamore]

On 18/03/2021 15:43, forax at univ-mlv.fr wrote:
> ----- Mail original -----
>> De: "Maurizio Cimadamore" <maurizio.cimadamore at oracle.com>
>> À: "Remi Forax" <forax at univ-mlv.fr>
>> Cc: "panama-dev at openjdk.java.net'" <panama-dev at openjdk.java.net>
>> Envoyé: Jeudi 18 Mars 2021 16:31:12
>> Objet: Re: Array of booleans
>> On 18/03/2021 15:28, forax at univ-mlv.fr wrote:
>>> It works with JNI, boolean is mapped into an unsigned 8 bits
>>> https://docs.oracle.com/en/java/javase/16/docs/specs/jni/types.html
>> Yeah - it seems to be a case of different specs pointing to different
>> decisions :-)
>>
>> If the format of booleans is truly unspecified at the JVMS level (which
>> seems to be the case), then it seems like JNI is taking things a step
>> too far?
> I don't think you can practically interact with the C world if you do not fully specify the memory layout of all the primitive types of Java, hence jboolean being defined as an unsigned byte.

True, but note that this is not a problem we have with the linker; the 
linker supports the C ABI. The only type related to boolean in e.g. the 
SysV ABI is _Bool, which is not a first-class type.

In other words, in Panama we can choose which primitives we wanna 
support - and also _how_ we wanna support them. It seems to me that 
boolean support is better handled in custom adapter logic at the user 
level, if the user really cares about its _Bool to come out as Java 
booleans?

Maurizio

>
>> Maurizio
> Rémi