[Pharo-users] FFI return by reference

[Thibault Raffaillac]

Hi again,

Does anyone know what is the state of return by reference in FFI?
Example:
glGetAttribute: attr into: value
        <primitive: #primitiveNativeCall module: #NativeBoostPlugin error: 
errorCode>
        ^ self nbCall: #( int SDL_GL_GetAttribute(SDL_GLattr attr, int *value) )

On my image (50666) it does nothing on value yet (if nil, remains nil, if 
SmallInteger 0, remains 0).
(SDL2 glGetAttribute: 6 into: value) should return 16.
I've seen NBOpenGL put "out" before value in method header, should it matter? 
(does not make it work though)
Last but not least, should we attach '*' to the type or variable for FFI to 
understand it is a pointer?

Cheers,
Thibault Raffaillac