[PPL-devel] [Fwd: Re: Some troubles I met while building PPL.]

[Enea Zaffanella]

Yuriy Taraday wrote:
> Oh, we didn't mention this function before.
> I'm curious why "const jobject&"? jobject - just a pointer and constant 
> referencing to a pointer looks pointless.

[...]

>     //! Returns a pointer to the C++ object wrapped by \p ppl_object.
>     void*
>     get_ptr(JNIEnv* env, const jobject& ppl_object);


I guess that, since we are not JNI experts, we just tried to take a 
safer approach whereby the `jobject' datatype is treated as a black box.

Usually, when we need to pass a "black box" datatype as an argument, we 
pass it by reference; since we do not need to modify it in this 
function, we also qualify it using const.

I just realized that we haven't been fully systematic in this respect, 
since we also have the helper function

//! Returns \c true if and only if \p obj is a null Java reference.
jboolean is_null(JNIEnv* env, jobject obj);

which is passing its jobject argument by copy.

Cheers,
Enea Zaffanella.