With last nVidia implementation clBuildProgram called with a callback function doesn't return immediately.

Reading the specification :
If pfn_notify is not NULL, clBuildProgram does not need to wait for the build to complete and can return immediately
, I guess this asynchronous call is implementation dependent... so I'll have to call clBuildProgram in a new thread, if want to always have an asynchronous behavior.

Is there a way to know if a context's compiler will build program asynchronously?