I need the following C function in Python:
int func(Uint8 *bytRecvBuffer, int *iRecvLen);
I tried in Python:
mydll = cdll.LoadLibrary("my.dll")
recvBuffer = None
recvLength = None
funcFunction = getattr(mydll, "func")
funcFunction(POINTER(c_ubyte(recvBuffer)), POINTER(c_int(recvLength)))
Error message:
TypeError: an integer is required
What is wrong here with the parameters?
You'll need to allocate an actual buffer and integer:
from ctypes import *
mydll = CDLL("my")
recvBuffer = create_string_buffer(1000)
recvLength = c_int(1000)
mydll.func(recvBuffer,byref(recvLength))
You can also declare the specific parameters supported by func, but then you must also be more explicit about the parameters passed:
mydll.func.argtypes = [POINTER(c_ubyte),POINTER(c_int)]
mydll.func.restype = c_int
recvBuffer = (c_ubyte*1000)()
recvLength = c_int(1000)
mydll.func(recvBuffer,byref(recvLength))
None is not integer.
c_int(None) causes TypeError
Init your variables with 0, not None
Did you try loading the dll with windll instead of cdll? also....isn't it pointer instead of POINTER ?
POINTER(type) takes a type and creates a pointer type for that type. pointer(instance) takes an instance and instantiates a pointer to that instance.Guessing from your initialization of recvBuffer and recvLength you want to create null pointer.
In that case you should create an instance without argument of specific type, do the following:
recvBuffer = POINTER(c_ubyte)()
recvLength = POINTER(c_int)()
funcFunction(recvBuffer, recvLength)
if you got the buffer within python, you need to cast your fixed size array to the correct pointer type.
