[英]Python ctypes: how to pass ctypes array to DLL?
Calling a dll from Python using ctypes , I want to pass a ctypes array to the dll . 使用ctypes从Python调用dll ,我想将ctypes数组传递给dll 。 Here is the Python code:
这是Python代码:
ReturnVec = ctypes.c_float * len(arrA)
t = type(ReturnVec)
hllDll = ctypes.WinDLL(r"C:/Temp2/Test_Project_3B/Std_Math_Formulas.dll")
SimpleTest = hllDll.SimpleTest
SimpleTest.argtypes = [ctypes.c_void_p, ctypes.POINTER(ctypes.c_float)]
SimpleTest.restype = ctypes.c_void_p
retvar = SimpleTest(ctypes.byref(pvarr),ctypes.c_float(ReturnVec))
The final line throws the error: 最后一行抛出错误:
"TypeError: must be real number, not _ctypes.PyCArrayType."
“ TypeError:必须为实数,而不是_ctypes.PyCArrayType。”
The variable t
shows that its type is ctypes.PyCArrayType
. 变量
t
显示其类型为ctypes.PyCArrayType
。 The variable ReturnVec
shows that its type is c_floatarray_1000
(where 1000
is the length of the array). 变量
ReturnVec
显示其类型为c_floatarray_1000
(其中1000
是数组的长度)。
I try to cast it to a float
: 我尝试将其转换为
float
:
aq = ctypes.cast(ReturnVec, ctypes.c_float)
but it returns: 但它返回:
"<class 'TypeError'>: wrong type"
“ <class'TypeError'>:错误的类型”
I try to cast it to a pointer, I get the same thing: 我尝试将其强制转换为指针,但得到相同的结果:
floatPtr = ctypes.cast(ReturnVec, ctypes.POINTER(ctypes.c_float))
I've researched this at length, and there are many threads on this issue, but none described my situation. 我对此进行了详尽的研究,并且在这个问题上有很多话题,但是没有人描述我的情况。
Here is the answer to my question above: 这是我上面的问题的答案:
SimpleTest = hllDll.SimpleTest SimpleTest = hllDll.SimpleTest
SimpleTest.argtypes = [ctypes.c_void_p, ctypes.c_void_p] SimpleTest.argtypes = [ctypes.c_void_p,ctypes.c_void_p]
SimpleTest.restype = ctypes.c_int64 SimpleTest.restype = ctypes.c_int64
retvar = SimpleTest(ctypes.byref(pvarr),ctypes.byref(arrA)) retvar = SimpleTest(ctypes.byref(pvarr),ctypes.byref(arrA))
ReturnVec
is a type , hence the "must be a real number" error. ReturnVec
是类型 ,因此“必须是实数”错误。 You need an instance of the type: 您需要一个类型的实例:
ReturnVecInstance = ReturnVec()
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