Empty values in return for ctypes pointer to int array - ctypes

Question

I'm currently trying to interface the following library (http://sol.gfxile.net/escapi/) using ctypes but I"m unsure if I'm doing something wrong or the library isn't working as I expect (sample c applications seem to work)
There is a struct that you are meant to pass to initCapture that looks like this
struct SimpleCapParams
{
/* Target buffer.
* Must be at least mWidth * mHeight * sizeof(int) of size!
*/
int * mTargetBuf;
/* Buffer width */
int mWidth;
/* Buffer height */
int mHeight;
};
This is my current code:
from ctypes import cdll, Structure, c_int, POINTER, cast, c_long, pointer
class SimpleCapParams(Structure):
_fields_ = [
("mTargetBuf", POINTER(c_int)),
("mWidth", c_int),
("mHeight", c_int)
]
width, height = 512, 512
array = (width * height * c_int)()
options = SimpleCapParams()
options.mWidth = width
options.height = height
options.mTargetBuf = array
lib = cdll.LoadLibrary('escapi.dll')
lib.initCOM()
lib.initCapture(0, options)
lib.doCapture(0)
while lib.isCaptureDone(0) == 0:
pass
print options.mTargetBuf
lib.deinitCapture(0)
However all the values in mTargetBuf are 0. Am I calling this wrong or something else going on?
This is a C++ example of what I need to do (without the ASCII): https://github.com/jarikomppa/escapi/blob/master/simplest/main.cpp

Answer 1

So seems I should check my code :)
options.height = height should be options.mHeight = height as per my structure.
The byref also helped.
Working code:
from ctypes import *
width, height = 512, 512
class SimpleCapParms(Structure):
_fields_ = [
("mTargetBuf", POINTER(c_int)),
("mWidth", c_int),
("mHeight", c_int),
]
array_type = (width * height * c_int)
array = array_type()
options = SimpleCapParms()
options.mWidth = width
options.mHeight = height
options.mTargetBuf = array
lib = cdll.LoadLibrary('escapi.dll')
lib.initCapture.argtypes = [c_int, POINTER(SimpleCapParms)]
lib.initCapture.restype = c_int
lib.initCOM()
lib.initCapture(0, byref(options))
lib.doCapture(0)
while lib.isCaptureDone(0) == 0:
pass
print(array[100])
lib.deinitCapture(0)