On one of my compile platforms, GCC was giving conversion warnings from
any boost include that was not wrapped in pragmas to disable conversion
warnings. To make things easier and more robust, I created a pair of
macros, VTKM_BOOST_PRE_INCLUDE and VTKM_BOOST_POST_INCLUDE, that should
be wrapped around any #include of a boost header file.
MSVC is picky about type conversions. To get it to shut up, explicitly
cast the worklet return value to the fetch value in the
WorkletInvokeFunctor. The good is that it will help with needing
explicit conversions on these return values. But that is also bad in
that it might make some unexpected conversions possible.
One fix is a simple (pointless) compiler warning about precision. The
other fix is an error in one of the test codes that did not clear out
the message string in an error message buffer like it was supposed to.
These changes support the implementation of DispatcherBase. This class
provides the basic functionality for calling an Invoke method in the
control environment, transferring data to the execution environment,
scheduling threads in the execution environment, pulling data for each
calling of the worklet method, and actually calling the worklet.
Whenever creating a functor to be launched in the execution environment
using the device adapter Schedule algorithm, you had to also create a
couple of methods to handle error message buffers. For convenience, lots
of code started to just inherit from WorkletBase. Although this worked,
it was a misnomer (and might cause problems in the future if worklets
later require different things from its base). To get around this
problem, add a FunctorBase class that is intended to be used as the
superclass to functors called with Schedule.
