C/C++与Python互相调用
一、【C/C++调用Python】
参考：http://www.open-open.com/lib/view/open1329532219656.html
1、例程：
test.c
#include "Python.h"
void HelloWorld(){
Py_Initialize();
PyRun_SimpleString("import sys");
PyRun_SimpleString("print 'hi,python!'");
PyRun_SimpleString("sys.path.append('./')");
PyObject * pModule = NULL;
PyObject * pFunc = NULL;
printf("11111 %x\n",pModule);
pModule =PyImport_ImportModule("mypy");
printf("11111 %x\n",pModule);
pFunc= PyObject_GetAttrString(pModule, "HelloWorld");
PyEval_CallObject(pFunc, NULL);
Py_Finalize();
}
void main(){
printf("tttttt\n");
HelloWorld();
}
mypy.py
#!/usr/bin/env python print '2222' def HelloWorld(): print 'this is Helloworld'
编译: mips-linux-gnu-gcc -EL test.c -L./lib -lpython2.7 -I./include/python2.7/
2、例程：
test.cpp
#include <iostream>
#include "Python.h"
using namespace std;
void HelloWorld();
void Add();
void TestTransferDict();
void TestClass();
int main()
{
cout << "Starting Test..." << endl;
cout << "HelloWorld()-------------" << endl;
HelloWorld();
cout << "Add()--------------------" << endl;
Add();
cout << "TestDict-----------------" << endl;
TestTransferDict();
cout << "TestClass----------------" << endl;
TestClass();
// system("pause");
return 0;
}
void HelloWorld()
{
Py_Initialize();
PyRun_SimpleString("import sys");
PyRun_SimpleString("print 'hi,python!'");
PyRun_SimpleString("sys.path.append('./')");
PyObject * pModule = NULL;
PyObject * pFunc = NULL;
pModule =PyImport_ImportModule("Test001");
pFunc= PyObject_GetAttrString(pModule, "HelloWorld");
PyEval_CallObject(pFunc, NULL);
Py_Finalize();
}
void Add()
{
Py_Initialize();
PyRun_SimpleString("import sys");
PyRun_SimpleString("sys.path.append('./')");
PyObject * pModule = NULL;
PyObject * pFunc = NULL;
pModule =PyImport_ImportModule("Test001");
pFunc= PyObject_GetAttrString(pModule,"add");
PyObject *pArgs = PyTuple_New(2);
PyTuple_SetItem(pArgs, 0, Py_BuildValue("i", 5));
PyTuple_SetItem(pArgs, 1, Py_BuildValue("i", 7));
PyObject *pReturn = NULL;
pReturn = PyEval_CallObject(pFunc, pArgs);
int result;
PyArg_Parse(pReturn, "i", &result);
cout << "5+7 = " << result << endl;
Py_Finalize();
}
void TestTransferDict()
{
Py_Initialize();
PyRun_SimpleString("import sys");
PyRun_SimpleString("sys.path.append('./')");
PyObject * pModule = NULL;
PyObject * pFunc = NULL;
pModule =PyImport_ImportModule("Test001");
pFunc= PyObject_GetAttrString(pModule, "TestDict");
PyObject *pArgs = PyTuple_New(1);
PyObject *pDict = PyDict_New();
PyDict_SetItemString(pDict, "Name", Py_BuildValue("s", "WangYao"));
PyDict_SetItemString(pDict, "Age", Py_BuildValue("i", 25));
PyTuple_SetItem(pArgs, 0, pDict);
PyObject *pReturn = NULL;
pReturn = PyEval_CallObject(pFunc, pArgs);
int size = PyDict_Size(pReturn);
cout <<"TTTTTTTT" << size << endl;
PyObject *pNewAge = PyDict_GetItemString(pReturn, "Age");
int newAge;
PyArg_Parse(pNewAge, "i", &newAge);
cout << "True Age: " << newAge << endl;
Py_Finalize();
}
void TestClass()
{
Py_Initialize();
PyRun_SimpleString("import sys");
PyRun_SimpleString("sys.path.append('./')");
PyObject * pModule = NULL;
PyObject * pFunc = NULL;
pModule =PyImport_ImportModule("Test001");
pFunc= PyObject_GetAttrString(pModule, "TestDict");
PyObject *pClassPerson = PyObject_GetAttrString(pModule, "Person");
PyObject *pInstancePerson = PyInstance_New(pClassPerson, NULL, NULL);
PyObject_CallMethod(pInstancePerson, "greet", "s", "Hello Kitty");
Py_Finalize();
}
Test001.py
def HelloWorld():
print "Hello World"
def add(a, b):
return a+b
def TestDict(dict):
print dict
dict["Age"] = 17
return dict
class Person:
def greet(self, greetStr):
print greetStr
#print add(5,7)
#a = raw_input("Enter To Continue...")
3、
其中
PyRun_SimpleString("import sys");
PyRun_SimpleString("sys.path.append('./')");
分别导入sys，接着设置py文件的路径
4、PySys_SetArgv、PySys_SetPath和PyRun_AnyFile的用法：
test1.c
#include "Python.h"
void HelloWorld(){
char *argv[2];
unsigned int argc;
argc = 2;
char *tmp="hello";
char *tmp1="world";
argv[0]= tmp;
argv[1]= tmp1;
Py_Initialize();
PySys_SetArgv(argc, argv);
PySys_SetPath("./");
// PyRun_SimpleString("import sys");
// PyRun_SimpleString("sys.path.append('./')");
PyRun_SimpleString("print 'hi,python!'");
PyObject * pModule = NULL;
PyObject * pFunc = NULL;
pModule =PyImport_ImportModule("mypy");
Py_Finalize();
}
void main(){
printf("tttttt\n");
HelloWorld();
}
mypy.py
#!/usr/bin/env python import sys print '----sys.argv[0]: ',sys.argv[0] print '----sys.argv[1]: ',sys.argv[1] print '2222' def HelloWorld(): print 'this is Helloworld' if __name__ == '__main__': print 'this is main
PySys_SetArgv，设置参数；
PySys_SetPath，设置py文件路径；如果要设置多个路径，在linux环境下可以用冒号:隔开，如：
PySys_SetPath("./:/usr/lib/python2.7:/usr/lib/python2.7/lib-dynload");
如果用下面的代码：
PyObject* file = PyFile_FromString((char *) "mypy.py", (char*)"r");
FILE *fp = PyFile_AsFile(file);
PyRun_AnyFile(fp,"mypy.py");
来代替：
PyObject * pModule = NULL;
pModule =PyImport_ImportModule("mypy");
也可以执行mypy.py，但是PyRun_AnyFile会执行mypy.py中的__main__中的代码；
有关run file的其他类似操作请参照：http://docs.python.org/2/c-api/veryhigh.html
二、【Python调用C/C++】
Python开发效率高，运行效率低。而c/c++恰恰相反。因此在python脚本中调用c/c++的库，对python进行扩展，是很有必要的。使用python api，http://www.python.org/doc/
1、
参考：http://www.oschina.net/question/234345_48628
test.c
#include <stdio.h>
void display() {
printf("This is Display Function\n");
}
gcc -shared -fpic test.c -o libtestso1.so -I./include/python2.7
test.py
import ctypes
so = ctypes.CDLL("./libtestso1.so")
so.display()
2、
testso2.cpp
#include<iostream>
class TestLib{
public:
void display();
void display(int a);
};
void TestLib::display() {
std::cout<<"First display"<<std::endl;
}
void TestLib::display(int a) {
std::cout<<"Second display"<<std::endl;
}
extern "C" {
TestLib obj;
void display() {
obj.display();
}
void display_int() {
obj.display(2);
}
}
g++ -shared -fpic testso2.cpp -o libtestso2.so -I./include/python2.7/
testso2.py
import ctypes
so = ctypes.CDLL("./libtestso2.so")
so.display()
so.display_int(1)
3、
参考：http://blog.csdn.net/marising/article/details/2845339
testso.cpp
#include <python2.6/Python.h> //包含python的头文件
// 1 c/cpp中的函数
int my_c_function(const char *arg) {
int n = system(arg);
return n;
}
// 2 python 包装
static PyObject * wrap_my_c_fun(PyObject *self, PyObject *args) {
const char * command;
int n;
if (!PyArg_ParseTuple(args, "s", &command))//这句是把python的变量args转换成c的变量command
return NULL;
n = my_c_function(command);//调用c的函数
return Py_BuildValue("i", n);//把c的返回值n转换成python的对象
}
// 3 方法列表
static PyMethodDef MyCppMethods[] = {
//MyCppFun1是python中注册的函数名，wrap_my_c_fun是函数指针
{ "MyCppFun1", wrap_my_c_fun, METH_VARARGS, "Execute a shell command." },
{ NULL, NULL, 0, NULL }
};
int getTestInt(){
return 10;
}
// 4 模块初始化方法
PyMODINIT_FUNC initMyCppModule(void) {
//初始模块，把MyCppMethods初始到MyCppModule中
PyObject *m = Py_InitModule("MyCppModule", MyCppMethods);
if (m == NULL)
return;
PyModule_AddStringConstant(m, (char*)"testString", (char*)"this is test string");
PyModule_AddIntConstant(m,"testInt",getTestInt());
}
也可以使用PyArg_ParseTupleAndKeywords()来对参数进行解析；
mips-linux-gnu-g++ -EL -shared -fpic testso.cpp -o MyCppModule.so -L./lib -lpython2.7 -I./include/python2.7/
testso.py
# -*- coding: utf-8 -*-
import MyCppModule
#导入python的模块（也就是c的模块，注意so文件名是MyCppModule
r = MyCppModule.MyCppFun1("ls -l")
print r
print MyCppModule.testString
print MyCppModule.testInt
print "OK"
PS：PyModule_Create和Py_InitModule的区别：http://stackoverflow.com/questions/10509400/difference-between-pymodinit-func-and-pymodule-create
PyModule_AddStringConstant、PyModule_AddIntConstant的用法