c++ 调用 python

c++ 调用 python - 邓维 - 博客园

c++ 调用 python

• Makefile first: 
g++ t2.cpp -o t2 -I/usr/include/python2.7 -lpython2.7
• t2.cpp code

#include <python2.7/Python.h>
 #include <iostream>
 #include <string>
 
 void printDict(PyObject* obj)
 {
     if(!PyDict_Check(obj))
         return ;
 
     PyObject *k, *keys;
     keys = PyDict_Keys(obj);
 
     for(int i=0; i < PyList_GET_SIZE(keys); i++)
     {
         k = PyList_GET_ITEM(keys, i);
         char *c_name = PyString_AsString(k);
         printf("%s\n", c_name);
     }
 }
 
 int main(void)
 {
     Py_Initialize();
     if(!Py_IsInitialized())
         return -1;
     
     PyRun_SimpleString("import sys");
     //where you put your py file
     PyRun_SimpleString("sys.path.append('../')");
     //Import 
     PyObject* pModule = PyImport_ImportModule("pc");//no *.py
     if(!pModule)
     {
         printf("can't open python file!\n");
         return -1;
     }
     //Dict module
     PyObject* pDict = PyModule_GetDict(pModule);
     if(!pDict)
     {
         printf("can't find dictionary.\n");
         return -1;
     }
     printDict(pDict);
 
     PyObject *pFunHi = PyDict_GetItemString(pDict, "sayHi");
     PyObject_CallFunction(pFunHi, "s", "yourname");// @para1: obj, @para2: name
     //release
     Py_DECREF(pFunHi);
     
     //Contruct a obj , call it's function
     //Second Class
     PyObject *pClassSecond = PyDict_GetItemString(pDict , "Second");
     if(!pClassSecond)
     {
         printf("can't find second class.\n");
         return -1;
     }
     //Person Class
     PyObject *pClassPerson = PyDict_GetItemString(pDict, "Person");
     if(!pClassPerson)
     {
         printf("can't find Person class.\n");
         return -1;
     }
     //Construct Second Instance
     PyObject* pInstanceSecond = PyInstance_New(pClassSecond, NULL, NULL);
     if(!pInstanceSecond)
     {
         printf("can't create second instance.\n");
         return -1;
     }
     //Construct Person Instance
     PyObject *pInstancePerson = PyInstance_New(pClassPerson, NULL, NULL);
     if(!pInstancePerson)
     {
         printf("can't create Person instance.\n");
         return -1;
     }
 
     //pass Person Instance to Second Instance 
     PyObject_CallMethod(pInstanceSecond, "invoke", "O", pInstancePerson);
     PyObject_CallMethod(pInstanceSecond, "method2", "O", pInstancePerson);
 
     //call execute a py file
     PyRun_SimpleString("exec(compile(open('./1.py').read(),'1.py', 'exec'),locals(), globals())");
     //release
     Py_DECREF(pInstanceSecond);
     Py_DECREF(pInstancePerson);
     Py_DECREF(pClassSecond);
     Py_DECREF(pClassPerson);
     Py_DECREF(pModule);
     Py_Finalize();
 
     return 0;
 }



• pc.py ( I put it at ..(upper) dir )

#!/usr/bin/python
 
 class Person:
     def sayHi(self):
         print 'Hi'
 
 class Second:
     def invoke(self, obj):
         obj.sayHi()
     def method2(self, obj):
         print "this is method2"
 
 def sayHi(name):
     print 'Hi ,', name



• 1.py ( I put it at .(this) dir )

 #!/usr/bin/python

 print " hello exec python"

• output:

sayHi
 __builtins__
 __file__
 __package__
 Person
 Second
 __name__
 __doc__
 Hi , yourname
 Hi
 this is method2
  hello exec python

from http://hi.baidu.com/zhouhanqing/blog/item/75b6134f2bddd91cb2de051a.html edited some of code




• some extra info , try look at the following code test in python :

  {'__builtins__': <module '>>> locals() 
   __builtin__' (built-in)>, '__name__': '__main__', '__doc__': None, '__package__': None}
   >>> globals()
   {'__builtins__': <module '__builtin__' (built-in)>, '__name__': '__main__', '__doc__': None, '__package__': None}
   >>> execfile("/home/dengwei/python_test/cpp/1.py")
    hello exec python
   >>> execfile("~/python_test/cpp/1.py")
   Traceback (most recent call last):
     File "<stdin>", line 1, in <module>
   IOError: [Errno 2] No such file or directory: '~/python_test/cpp/1.py'

  • 1.locals()
  • 2.globals()
  • 3.how to exec a python file (in python)
  • 4.we knows exec a python file should specify it's absolute path

Now we know