Does Ctypes Structures and POINTERS automatically free the memory when the Python object is deleted?
- by jsbueno
When using Python CTypes there are the Structures, that allow you to clone c-structures on the Python side, and the POINTERS objects that create a sofisticated Python Object from a memory address value and can be used to pass objects by reference back and forth C code.
What I could not find on the documentation or elsewhere is what happens when a Python object containing a Structure class that was de-referenced from a returning pointer from C Code (that is - the C function alocated memory for the structure) is itself deleted. Is the memory for the original C structure freed? If not how to do it?
Furthermore -- what if the Structure contains Pointers itself, to other data that was also allocated by the C function? Does the deletion of the Structure object frees the Pointers onits members? (I doubt so) Else - -how to do it? Trying to call the system "free" from Python for the Pointers in the Structure is crashing Python for me.
In other words, I have this structure filled up by a c Function call:
class PIX(ctypes.Structure):
"""Comments not generated
"""
_fields_ = [
("w", ctypes.c_uint32),
("h", ctypes.c_uint32),
("d", ctypes.c_uint32),
("wpl", ctypes.c_uint32),
("refcount", ctypes.c_uint32),
("xres", ctypes.c_uint32),
("yres", ctypes.c_uint32),
("informat", ctypes.c_int32),
("text", ctypes.POINTER(ctypes.c_char)),
("colormap", ctypes.POINTER(PIXCOLORMAP)),
("data", ctypes.POINTER(ctypes.c_uint32))
]
And I want to free the memory it is using up from Python code.
