Most of the information in this chapter uses C syntax, extended with two additional keywords:
NOTNULLThe NOTNULL keyword means that this function argument must not be a null pointer.
In Python, where None is used as the null pointer value, there will be an exception thrown if such a function is called with a None value.
PYTHON_METHODMost interfaces are in canonical form; i.e., they only contain function pointers, and the first argument is always the object whose interface is called.
For non-canonical interfaces, the keyword PYTHON_METHOD is used to mark regular methods.
These should be called without their first argument when used from Python.
Note that there is no special mark-up for canonical interfaces.