* It's required by MPI_Pack_size.

that allows for better type safety in argument passing.

* Return invalid id in case the user passed an invalid method.

* gcc is confused wrt control flow.

* interface changed in r936.

* previously an undefined value was returned when id was not found.

* This is relevant only in case no match is found.

* control flow confused gcc.

* A print conversion needed to be adjusted accordingly.

* It doesn' deliver significantly more functionality than assert.

compiled region controlled by same conditional.

* gcc could not establish that writerIdx was always initialized here.