使用Cype调用带有Python参数的C++方法导致“不知道如何转换参数”错误

我试图从Python 3使用下面的C++类。7,但无法让第一个方法“设置”工作,更不用说运算符重载方法了。我尝试了Python包装器和extern块的许多变体,但我要么遇到了“不知道如何转换参数5”错误,要么遇到了分段错误。网上的例子和我找到的答案都太基本了,或者是解决了其他问题。

我的argtypes第一个参数应该是指向对象的指针吗?我不知道用什么语法来表示。

CMatrix。h:

#include <stdio.h>

class CMatrix
{
public:
    CMatrix(int d1);
    CMatrix(int d1, int d2);
    CMatrix(int d1, int d2, int d3);
    CMatrix (float f1, float f2, float f3);
    ~CMatrix();
    
    void Set(int x, int y, int z, float f);
    void operator=(const float f);
    CMatrix& operator=(const CMatrix &cm);
    inline float& operator()(const int i) {
        return m[i];}
    inline float& operator()(const int i, const int j) {
        return m[i*s2+j];}
    inline float& operator()(const int i, const int j, const int k) {
        return m[i*s23+j*s3+k];}
    int s1, s2, s3;     // dimensions of array
    int s23;            // s2*s3;
    float *m;           // pointer to first element of matrix.
    int dimensions;     // 1, 2, or 3.
};

extern "C" {
    CMatrix* CMatrix_new1(int i) {return new CMatrix(i); }
    CMatrix* CMatrix_new2(int i, int j) {return new CMatrix(i, j); }
    CMatrix* CMatrix_new3(int i, int j, int k) {return new CMatrix(i, j, k); }
    void CMatrix_Set(CMatrix* cm, int x, int y, int z, float f) {cm->Set(x, y, z, f); }
}

cmWrapper。py:

import ctypes as c
lib = c.cdll.LoadLibrary('./libCMatrix.o')
lib.CMatrix_Set.argtypes = [c.c_int, c.c_int, c.c_int, c.c_float]

class CMatrix(object):
    def __init__(self, i, j, k):
        if j==0 and k==0:
            self.obj = lib.CMatrix_new1(i)
        elif k==0:
            self.obj = lib.CMatrix_new2(i, j)
        else:
            self.obj = lib.CMatrix_new3(i, j, k)

    def Set(self, x, y, z, f):
        lib.CMatrix_Set(self.obj, x, y, z, f)

cm = CMatrix(2, 3, 0)
cm.Set(1, 2, 0, 99.0)

追溯:

>>> import cmWrapper
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/.../ctypes/cmWrapper.py", line 18, in <module>
    cm.Set(1, 2, 0, 99.0)
  File "/.../ctypes/cmWrapper.py", line 15, in Set
    lib.CMatrix_Set(self.obj, x, y, z, f)
ctypes.ArgumentError: argument 5: <class 'TypeError'>: Don't know how to convert parameter 5

如果有问题,我用C++编译了C++代码:

g++ -c -fPIC CMatrix.cpp -o CMatrix.o
g++ -shared -Wl -o libCMatrix.o CMatrix.o

这是在运行10.15.7的Mac上。

来自lldb:

Executable module set to "/Library/Frameworks/Python.framework/Versions/3.7/Resources/Python.app/Contents/MacOS/Python".
Architecture set to: x86_64h-apple-macosx-.
(lldb) 
There is a running process, detach from it and attach?: [Y/n] n
(lldb) thread list
Process 57460 stopped
* thread #1: tid = 0x47364c, 0x00007fff202f5656 libsystem_kernel.dylib`__select + 10, queue = 'com.apple.main-thread', stop reason = signal SIGSTOP
(lldb) thread continue
Resuming thread 0x47364c in process 57460
Process 57460 resuming
Process 57460 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x13835f20)
    frame #0: 0x00000001015f19b2 libCMatrix.o`CMatrix::Set(int, int, int, float) + 34
libCMatrix.o`CMatrix::Set:
->  0x1015f19b2 <+34>: movl   (%rax), %esi
    0x1015f19b4 <+36>: movl   0x4(%rax), %edx
    0x1015f19b7 <+39>: movl   0x8(%rax), %ecx
    0x1015f19ba <+42>: movl   0xc(%rax), %r8d
Target 0: (Python) stopped.