Python支持C/C++实现的第3方扩展包，在性能要求高的场合，这种特性显得尤其重要。
本文以实例说明定制Python扩展包的基本步骤。
1. 扩展包源码实现
按照Python官网教程Extending Python with C or C++说明的步骤，扩展模块的源文件实现如下：#include <Python.h>
// forward declaration
void initpyext(void);
// self-defined error obj
static PyObject * ExtError;
int main(int argc, char * argv[])
{
// Pass argv[0] to the Python interpreter
Py_SetProgramName(argv[0]);
// Initialize the Python interpreter. Required.
Py_Initialize();
initpyext();
Py_Exit(0);
// not reached, warning will be printed when build the extension
}
static PyObject * py_ext_test_func(PyObject * self, PyObject * args)
{
const char * command;
int sts;
if(!PyArg_ParseTuple(args, "s", &command)) {
return NULL;
}
sts = system(command);
if(sts < 0) {
PyErr_SetString(ExtError, "System command failed");
return NULL;
}
return PyLong_FromLong(sts);
}
static PyMethodDef PyextMethods[] = {
{"ext_cmd", py_ext_test_func, METH_VARARGS, "Execute a shell command." },
{NULL, NULL, 0, NULL}
};
PyMODINIT_FUNC initpyext(void)
{
PyObject * m;
m = Py_InitModule("pyext", PyextMethods);
if(NULL == m) {
return;
}
ExtError = PyErr_NewException("pyext.error", NULL, NULL);
Py_INCREF(ExtError);
PyModule_AddObject(m, "error", ExtError);
}上面的代码展示的是一个典型的针对Python的c扩展源码布局：2. 扩展文件编译/链接
根据官网文档Building C and C++ Extensions with distutils，可以这样编译扩展并安装至python第三方package目录：$> python setup.py build running build running build_ext building 'pyext' extension gcc -pthread -fno-strict-aliasing -g -O2 -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -fPIC -I/home/slvher/tools/python-2.7.5/include/python2.7 -c pyext.c -o build/temp.linux-x86_64-2.7/pyext.o pyext.c: In function `main': pyext.c:28: warning: control reaches end of non-void function gcc -pthread -shared build/temp.linux-x86_64-2.7/pyext.o -o build/lib.linux-x86_64-2.7/pyext.so注意：这里直接用python调用setup.py是因为在PATH中设置了python的默认环境变量，如果当前系统默认的python解释器不是我们想要用来编译扩展的解释器时，需要用python的绝对路径调用。
$> python setup.py install running install running build running build_ext running install_lib copying build/lib.linux-x86_64-2.7/pyext.so -> /home/slvher/tools/python-2.7.5/lib/python2.7/site-packages running install_egg_info Writing /home/slvher/tools/python-2.7.5/lib/python2.7/site-packages/TestPyExtPackage-1.0-py2.7.egg-info4. 验证是否可用
>>> import pyext
>>> pyext.ext_cmd("echo hello world")
hello world
0L
>>> 【参考资料】2. Building C and C++ Extensions with distutils
====================== EOF ==================
【Python笔记】如何用C语言实现Python第三方扩展包
原文地址：http://blog.csdn.net/slvher/article/details/39233765
