bool type

[simon-p-r]

Hi

I am trying to use a bool type however the value in c code is not true or false, I have tried these 2 different ways

const traceMode = ref.alloc('bool', 1); // true

and

const traceMode = ref.alloc(ref.types.bool, 1); // true

Any pointers would be appreciated!

Thanks

[TooTallNate]

Is it possible to show me a more complete sample code to demonstrate your problem? What C lib are you trying to invoke?

[simon-p-r]

I have just done a stripped down version of api, the C api is like this

void create(struct Obj *obj) {

   // value should be true
   if (obj->traceMode) {
       // do something
   }
}

Struct for c api is defined like this

struct Obj {
    bool traceMode;
}

It is defined and used in javascript like this

const Obj = Struct({
    traceMode: ref.types.bool
});

const newObj = new Obj({
    traceMode: ref.alloc('bool', 1) // have also tried ref.alloc(ref.types.bool, 1) as well
});

const structPtr = ref.refType(Obj);

const lib = ffi.Library(dllPath, { 
    'create': ['void', [structPtr]]
});

lib.create(newObj.ref());

[TooTallNate]

Oh I see. You don't need to do the ref.alloc() part. Just pass JS true or false in and ref.types.bool handles the coercion to the C value:

const newObj = new Obj({
    traceMode: true
});

What you were doing was passing in a pointer to a bool, which was an address in memory which would basically always be "true".

[simon-p-r]

Ok I will try that, thanks for your swift answer!

[simon-p-r]

I am testing value of bool inside c like this but it still doesn't recognise the ref past from javascript.

if (obj->traceMode) {
    printf("Trace mode is on\n");
}
else {
    prinf("Trace mode is off\n");
}

[TooTallNate]

@simon-p-r I added a test case in https://github.com/node-ffi/node-ffi/commit/7a928f38b1f7520035cfb6607391b9d7c8acb739 which seems to be working as expected. Let me know if I'm missing anything.

[simon-p-r]

Thanks @TooTallNate forgot about this, I think my problem was a boundary problem with the struct I was working with. I am a total c novice, thanks for this excellent module!