python调用c++ ctype list传数组或者返回数组的方法

示例1：

pycallclass.cpp：

#include <iostream>
using namespace std;
typedef unsigned char BYTE;
#define MAX_COUNT 20

struct tagOutCardResult_py
{
BYTEcbCardCount;
BYTEcbResultCard1;
BYTEcbResultCard2;
BYTEcbResultCard3;
BYTEcbResultCard4;
BYTEcbResultCard5;
BYTEcbResultCard6;
BYTEcbResultCard7;
BYTEcbResultCard8;
BYTEcbResultCard9;
BYTEcbResultCard10;
BYTEcbResultCard11;
BYTEcbResultCard12;
BYTEcbResultCard13;
BYTEcbResultCard14;
BYTEcbResultCard15;
BYTEcbResultCard16;
BYTEcbResultCard17;
BYTEcbResultCard18;
BYTEcbResultCard19;
BYTEcbResultCard20;
};

struct tagOutCardResult
{
BYTEcbCardCount;
BYTEcbResultCard[MAX_COUNT];
void clear()
{
cbCardCount = 0;
for (int nIdx = 0;nIdx < MAX_COUNT;++nIdx)
{
cbResultCard[nIdx] = 0;
}
}
void topy(tagOutCardResult_py* ppy)
{
cout<<"topy function begin"<<endl;
ppy->cbCardCount = cbCardCount;
cout<<"topy function 1"<<endl;
ppy->cbResultCard1 = cbResultCard[1 - 1];
cout<<"topy function 2"<<endl;
ppy->cbResultCard2 = cbResultCard[2 - 1];
ppy->cbResultCard3 = cbResultCard[3 - 1];
ppy->cbResultCard4 = cbResultCard[4 - 1];
ppy->cbResultCard5 = cbResultCard[5 - 1];
ppy->cbResultCard6 = cbResultCard[6 - 1];
ppy->cbResultCard7 = cbResultCard[7 - 1];
ppy->cbResultCard8 = cbResultCard[8 - 1];
ppy->cbResultCard9 = cbResultCard[9 - 1];
ppy->cbResultCard10 = cbResultCard[10 - 1];
ppy->cbResultCard11 = cbResultCard[11 - 1];
ppy->cbResultCard12 = cbResultCard[12 - 1];
ppy->cbResultCard13 = cbResultCard[13 - 1];
ppy->cbResultCard14 = cbResultCard[14 - 1];
ppy->cbResultCard15 = cbResultCard[15 - 1];
ppy->cbResultCard16 = cbResultCard[16 - 1];
ppy->cbResultCard17 = cbResultCard[17 - 1];
ppy->cbResultCard18 = cbResultCard[18 - 1];
ppy->cbResultCard19 = cbResultCard[19 - 1];
ppy->cbResultCard20 = cbResultCard[20 - 1];
cout<<"topy function end"<<endl;
}
};

class TestLib
{
public:
void display(tagOutCardResult& ret);
};
void TestLib::display(tagOutCardResult& ret) {
ret.cbCardCount = 3;
ret.cbResultCard[0] = 1;
ret.cbResultCard[1] = 50;
ret.cbResultCard[2] = 100;

cout<<"First display aaa ";
cout<<"hello ";
cout<<"world ";
}

extern "C" {
TestLib oGameLogic;
void display(tagOutCardResult_py* ret_py) {
tagOutCardResult oRet;
oGameLogic.display(oRet);
cout<<"before topy"<<endl;
oRet.topy(ret_py);
cout<<"after topy"<<endl;
cout<<"in cpp:ret_py->cbCardCount:"<<ret_py->cbCardCount<<endl;
cout<<"in cpp:ret_py->cbResultCard1:"<<ret_py->cbResultCard1<<endl;
cout<<" this:" << ret_py << endl;
}
}

编译脚本：

g++ -o libpycallclass.so -shared -fPIC pycallclass.cpp -I/usr/include/python2.6 -L/usr/lib64/python2.6/config

Game.py调用部分。类声明：

import ctypes

class tagOutCardResult_py(ctypes.Structure):
_fields_ = [("cbCardCount", ctypes.c_ubyte), \
("cbResultCard1", ctypes.c_ubyte), \
("cbResultCard2", ctypes.c_ubyte), \
("cbResultCard3", ctypes.c_ubyte), \
("cbResultCard4", ctypes.c_ubyte), \
("cbResultCard5", ctypes.c_ubyte), \
("cbResultCard6", ctypes.c_ubyte), \
("cbResultCard7", ctypes.c_ubyte), \
("cbResultCard8", ctypes.c_ubyte), \
("cbResultCard9", ctypes.c_ubyte), \
("cbResultCard10", ctypes.c_ubyte), \
("cbResultCard11", ctypes.c_ubyte), \
("cbResultCard12", ctypes.c_ubyte), \
("cbResultCard13", ctypes.c_ubyte), \
("cbResultCard14", ctypes.c_ubyte), \
("cbResultCard15", ctypes.c_ubyte), \
("cbResultCard16", ctypes.c_ubyte), \
("cbResultCard17", ctypes.c_ubyte), \
("cbResultCard18", ctypes.c_ubyte), \
("cbResultCard19", ctypes.c_ubyte), \
("cbResultCard20", ctypes.c_ubyte)]

Game.py调用部分。具体调用：

 import ctypes
 so = ctypes.cdll.LoadLibrary
 lib = so("./libpycallclass.so")
 ERROR_MSG('display(\)')
 ret = tagOutCardResult_py(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
 ERROR_MSG("before lib.display(ctypes.byref(ret))")
 lib.display(ctypes.byref(ret))
 ERROR_MSG("after lib.display(ctypes.byref(ret))")
 ERROR_MSG('#######################################################################################')
 ERROR_MSG(ret)
 ERROR_MSG(ret.cbCardCount)
 ERROR_MSG(ret.cbResultCard1)
 ERROR_MSG(ret.cbResultCard2)
 ERROR_MSG(ret.cbResultCard3)
 ERROR_MSG(type(ret))

传入一个结构体，使用引用返回，回到python中打印出来结果是对的。

这样就可以传入，可以传出了。

示例1end#########################################################################

示例2：

pycallclass.cpp:

#include <iostream>
using namespace std;
typedef unsigned char BYTE;
#define MAX_COUNT 20

#if defined(WIN32)||defined(WINDOWS)
#define DLL_EXPORT __declspec(dllexport)
#else
#define DLL_EXPORT
#endif

struct ByteArray_20
{
BYTE e1;
BYTE e2;
BYTE e3;
BYTE e4;
BYTE e5;
BYTE e6;
BYTE e7;
BYTE e8;
BYTE e9;
BYTE e10;
BYTE e11;
BYTE e12;
BYTE e13;
BYTE e14;
BYTE e15;
BYTE e16;
BYTE e17;
BYTE e18;
BYTE e19;
BYTE e20;
};
struct ByteArray_20_3
{
ByteArray_20 e1;
ByteArray_20 e2;
ByteArray_20 e3;
};

struct ByteArrayNew_20_3
{
BYTE e[3][20];
};

class TestLib
{
public:
void LogicFunc(ByteArray_20_3& ret);
void LogicFuncNew(ByteArrayNew_20_3& ret);
};
void TestLib::LogicFunc(ByteArray_20_3& ret) {
ret.e1.e1 = 3;
ret.e1.e2 = 1;
ret.e1.e3 = 50;
ret.e2.e1 = 100;
ret.e2.e2 = 200;
ret.e2.e3 = 20;

cout<<"TestLib::LogicFunc"<<endl;
}
void TestLib::LogicFuncNew(ByteArrayNew_20_3& ret) {
ret.e[0][0] = 31;
ret.e[0][1] = 11;
ret.e[0][2] = 51;
ret.e[1][0] = 101;
ret.e[1][1] = 201;
ret.e[1][2] = 21;

cout << "TestLib::LogicFuncNew" << endl;
}

extern "C" {
TestLib oGameLogic;
void DLL_EXPORT display(ByteArray_20_3* pret) {
cout<<"cpp display func begin"<<endl;
oGameLogic.LogicFunc(*pret);
cout<<"cpp display func end"<<endl;
}
void DLL_EXPORT display2(ByteArrayNew_20_3* pret) {
cout << "cpp display2 func begin" << endl;
oGameLogic.LogicFuncNew(*pret);
cout << "cpp display2 func end" << endl;
}
}

pycallclass.py:

import ctypes

def ERROR_MSG(str):
print str

class ByteArray_20(ctypes.Structure):
_fields_ = [\
("e1", ctypes.c_ubyte), \
("e2", ctypes.c_ubyte), \
("e3", ctypes.c_ubyte), \
("e4", ctypes.c_ubyte), \
("e5", ctypes.c_ubyte), \
("e6", ctypes.c_ubyte), \
("e7", ctypes.c_ubyte), \
("e8", ctypes.c_ubyte), \
("e9", ctypes.c_ubyte), \
("e10", ctypes.c_ubyte), \
("e11", ctypes.c_ubyte), \
("e12", ctypes.c_ubyte), \
("e13", ctypes.c_ubyte), \
("e14", ctypes.c_ubyte), \
("e15", ctypes.c_ubyte), \
("e16", ctypes.c_ubyte), \
("e17", ctypes.c_ubyte), \
("e18", ctypes.c_ubyte), \
("e19", ctypes.c_ubyte), \
("e20", ctypes.c_ubyte)]

class ByteArray_20_3(ctypes.Structure):
_fields_ = [\
("e1", ByteArray_20), \
("e2", ByteArray_20), \
("e3", ByteArray_20)]
def __init__(self):
 self.aaa = 123
 self.bbb = [1, 2, 3, 4, 5]
 self.ccc = "alksdfjlasdfjk"
def test(self):
 self.aaa = 123
 self.bbb = [1, 2, 3, 4, 5]
 self.ccc = "alksdfjlasdfjk"
 self.e1.e1 = 5
 self.e1.e2 = 20

so = ctypes.cdll.LoadLibrary
lib = so("./libpycallclass.dll")
print('display()')
ret = ByteArray_20_3()
ret.test()
ERROR_MSG(ret.e1.e1)
ERROR_MSG(ret.e1.e2)
print("before lib.display(ctypes.byref(ret))")
lib.display(ctypes.byref(ret))
print("after lib.display(ctypes.byref(ret))")
print('#######################################################################################')
print(ret)
ERROR_MSG(ret.e1)
ERROR_MSG(ret.e2)
ERROR_MSG(ret.e3)
ERROR_MSG(ret.e1.e1)
ERROR_MSG(ret.e1.e2)
ERROR_MSG(ret.e1.e3)
ERROR_MSG(ret.e2.e1)
ERROR_MSG(ret.e2.e2)
ERROR_MSG(ret.e2.e3)
ERROR_MSG(type(ret))

print("before lib.display2(ctypes.byref(ret))")
lib.display2(ctypes.byref(ret))
print("after lib.display2(ctypes.byref(ret))")
print('#######################################################################################')
print(ret)
ERROR_MSG(ret.e1)
ERROR_MSG(ret.e2)
ERROR_MSG(ret.e3)
ERROR_MSG(ret.e1.e1)
ERROR_MSG(ret.e1.e2)
ERROR_MSG(ret.e1.e3)
ERROR_MSG(ret.e2.e1)
ERROR_MSG(ret.e2.e2)
ERROR_MSG(ret.e2.e3)
ERROR_MSG(type(ret))

ret.test()
ERROR_MSG(ret.e1.e1)
ERROR_MSG(ret.e1.e2)

g++:

g++ -o libpycallclass.so -shared -fPIC pycallclass.cpp -I/usr/include/python2.6 -L/usr/lib64/python2.6/config

windows:

新建一个DLL工程，把pycallclass.cpp加进去，编译成DLL就OK了。

千万注意python的运行时是32位的还是64位的，DLL或者SO必须和它对应。

python类可以嵌套使用，继承ctypes.Structure，部分成员是_fields_里定义的，部分成员在__init__里定义，这样的类也可以ctypes.byref(self)传进c++去，传的是指针，传入传出就都OK了。

注意示例2中ByteArrayNew_20_3的用法，python中是定义了20个变量，c++中是直接一个二维数组。内存结构是一致的，所以可以直接这样使用。注意类型和长度必须一致，否则可能会内存访问越界。

来源：https://blog.csdn.net/uniqsa/article/details/78603082