Since mmap.resize uses MREMAP_MAYMOVE on Linux, it would be nice to warn users that pointers into their memory mapped regions will be invalid after resizes. Linux's manpage offers the following explanation:

"If the mapping is relocated, then absolute pointers into the old mapping location become invalid (offsets relative to the starting address of the mapping should be employed)."

Since the only way I know of to use pointers into mmaps from pure Python is to use ctypes.<type>.from_buffer(<mmap>), perhaps clarification would be better in the ctypes docs.