RFC: Array input arguments: allow annotating as mutable
In Python, objects can provide a buffer interface to expose the internal C arrays and modify them. This allows one to pass a pre allocated buffer as input and let the C function mutate it for the duration of the call.
In Python this used here for example: https://docs.python.org/3.6/library/io.html#io.RawIOBase.readinto where you can provide a buffer object and Python will fill it.
Examples which could use such annotation would be g_input_stream_read
, g_input_stream_read_all
Basically any array argument which is transfer-none where the called function will modify the input in-place.
Edited by Christoph Reiter