Python調用C/C++的種種方法

 Python調用C/C++的種種方法 Python是解釋性語言, 底層就是用c實現的, 因此用python調用C是很容易的, 下面就總結一下各類調用的方法, 給出例子, 全部例子都在ubuntu9.10, python2.6下試過.   1. Python 調用 C (base) 想在python中調用c函數, 如這兒的fact #include <Python.h> int fact(int n) {   if (n <= 1)     return 1;   else     return n * fact(n - 1); } PyObject* wrap_fact(PyObject* self, PyObject* args) {   int n, result;   if (! PyArg_ParseTuple(args, "i:fact", &n))     return NULL;   result = fact(n);   return Py_BuildValue("i", result); } static PyMethodDef exampleMethods[] = {   {"fact", wrap_fact, METH_VARARGS, "Caculate N!"},   {NULL, NULL} }; void initexample() {   PyObject* m;   m = Py_InitModule("example", exampleMethods); }   把這段代碼存爲wrapper.c, 編成so庫, gcc -fPIC wrapper.c -o example.so -shared  -I/usr/include/python2.6 -I/usr/lib/python2.6/config   而後在有此so庫的目錄, 進入python, 能夠以下使用 import example example.fact(4)   2. Python 調用 C++ (base) 在python中調用C++類成員函數, 以下調用TestFact類中的fact函數, #include <Python.h> class TestFact{     public:     TestFact(){};     ~TestFact(){};     int fact(int n); }; int TestFact::fact(int n) {   if (n <= 1)     return 1;   else     return n * (n - 1); } int fact(int n) {     TestFact t;     return t.fact(n); } PyObject* wrap_fact(PyObject* self, PyObject* args) {   int n, result;   if (! PyArg_ParseTuple(args, "i:fact", &n))     return NULL;   result = fact(n);   return Py_BuildValue("i", result); } static PyMethodDef exampleMethods[] = {   {"fact", wrap_fact, METH_VARARGS, "Caculate N!"},   {NULL, NULL} }; extern "C"              //不加會致使找不到initexample void initexample() {   PyObject* m;   m = Py_InitModule("example", exampleMethods); }   把這段代碼存爲wrapper.cpp, 編成so庫, g++ -fPIC wrapper.cpp -o example.so -shared -I/usr/include/python2.6 -I/usr/lib/python2.6/config   而後在有此so庫的目錄, 進入python, 能夠以下使用 import example example.fact(4)   3. Python 調用 C++ (Boost.Python) Boost庫是很是強大的庫, 其中的python庫能夠用來封裝c++被python調用, 功能比較強大, 不但能夠封裝函數還能封裝類, 類成員. http://dev.gameres.com/Program/Abstract/Building%20Hybrid%20Systems%20with%20Boost_Python.CHN.by.JERRY.htm 首先在ubuntu下安裝boost.python, apt-get install libboost-python-dev #include <boost/python.hpp> char const* greet() {    return "hello, world"; } BOOST_PYTHON_MODULE(hello) {     using namespace boost::python;     def("greet", greet); } 把代碼存爲hello.cpp, 編譯成so庫 g++ hello.cpp -o hello.so -shared -I/usr/include/python2.5 -I/usr/lib/python2.5/config -lboost_python-gcc42-mt-1_34_1   此處python路徑設爲你的python路徑, 而且必須加-lboost_python-gcc42-mt-1_34_1, 這個庫名不必定是這個, 去/user/lib查   而後在有此so庫的目錄, 進入python, 能夠以下使用 >>> import hello >>> hello.greet() 'hello, world'   4. python 調用 c++ (ctypes) ctypes is an advanced ffi (Foreign Function Interface) package for Python 2.3 and higher. In Python 2.5 it is already included. ctypes allows to call functions in dlls/shared libraries and has extensive facilities to create, access and manipulate simple and complicated C data types in Python - in other words: wrap libraries in pure Python. It is even possible to implement C callback functions in pure Python. http://python.net/crew/theller/ctypes/   #include <Python.h> class TestFact{     public:     TestFact(){};     ~TestFact(){};     int fact(int n); }; int TestFact::fact(int n) {   if (n <= 1)     return 1;   else     return n * (n - 1); } extern "C" int fact(int n) {     TestFact t;     return t.fact(n); } 將代碼存爲wrapper.cpp不用寫python接口封裝, 直接編譯成so庫, g++ -fPIC wrapper.cpp -o example.so -shared -I/usr/include/python2.6 -I/usr/lib/python2.6/config   進入python, 能夠以下使用 >>> import ctypes >>> pdll = ctypes.CDLL('/home/ubuntu/tmp/example.so') >>> pdll.fact(4) 12