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'

Now we know


• 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