C扩展Python

基本想法： 先看中文小介绍，再看英文详细文档。

1. 参考

首先参考THIS， IBM的工程师好像出了好多这样的文章啊，而且每次看到时间戳，我都想戳自己- -!

2. ERROR

可能遇到错误： fatal error: Python.c: No such file or directory

a. 参考THIS ；  b. 或许用  sudo apt-get install python2.7-dev，命令就能解决（江湖传闻，只用于ubuntu） ； c. python2.7-dev 是什么？THIS

3. 参考

参考《Python core programming》- Chapter 22, 扩展Python - 全部看一遍，

注意到了 strdup() 函数。联想到和 strcpy() 函数 的区别。

关于 strdup() 的解说 参考 THIS

（这里，我一开始以为，下面的答案有 memory leak，但是注意返回值char*， 注意在《Python core programming》 中的用法，

说明，如果你使用 p= strdup()，就需要你自己再次 free(p) ， 对我来说，这就是最重要的区别。）

4. ERROR

$ python setup.py install

running install
running build
running build_ext
running install_lib
copying build/lib.linux-i686-2.7/Extest.so -> /usr/local/lib/python2.7/dist-packages
error: /usr/local/lib/python2.7/dist-packages/Extest.so: Permission denied 

注意到，error发生。猜测是ubuntu 读写权限问题。

$ sudo python setup.py install
[sudo] password for usr:
running install
running build
running build_ext
running install_lib
copying build/lib.linux-i686-2.7/Extest.so -> /usr/local/lib/python2.7/dist-packages
running install_egg_info
Writing /usr/local/lib/python2.7/dist-packages/Extest-0.0.0.egg-info

问题解决。

5. 参考

a. 官方文档。

b. 应该是，中文翻译。面对这个翻译，我真的真的，尼玛很佩服啊！太tmd有用了啊！

—— THIS，这个货，尼玛啊！是做果壳网的！！?

c. THIS，虽然不是文档，但是看着还不错。

说实话，看了一些资料之后，对于 “C扩展Python”这个问题，所有资料都指向官方文档。完全是躲不开的文档。除非你不玩了。那你还能不玩很多事情。

6. 未解决

static PyObject *
spam_system(PyObject *self, PyObject *args) { ...}

self ??

The self argument points to the module object for module-level functions; for a method it would point to the object instance.

7. 未解决

where is

An example may be found in the file Demo/embed/demo.c in the Python source distribution.

where is

A more substantial example module is included in the Python source distribution as Modules/xxmodule.c. This file may be used as a template or simply read as an example.

8. 未解决

1.2， 1.4， 1.5， 1.6， 1.8需要例子，

C中调用Python，要十分小心 reference 的使用，很容易导致内存问题。

为什么所有的 要供给python使用的 封装函数，都要是static？

9. <Python cookbook> - chapter 17

-(17.1) Topic: C语言定义了一个新的类型，这个类型Python可以操作。

a. 在开始17.1之前，先完成 THIS.

b. PyObject_HEAD -> Py_ssize_t -> PyTypeObject -> PyObject

-> staticforward(注意：Python2.2中，定义新类型发生了变化。 Python2.7中，没有staticforward)

-> statichere(THIS1(ctrl+F: statichere); THIS2; In a word, both staticforward & statichere are just static now.)

-> PyArg_ParseTuple ->

未解决 - ERROR:

running build
running build_ext
building 'elemlist' extension
creating build
creating build/temp.linux-i686-2.7
gcc -pthread -fno-strict-aliasing -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -fPIC -I/usr/include/python2.7 -c elemlist.c -o build/temp.linux-i686-2.7/elemlist.o
elemlist.c: In function ‘car’:
elemlist.c:58:31: error: ‘PyObject’ has no member named ‘car’
elemlist.c: In function ‘cdr’:
elemlist.c:67:31: error: ‘PyObject’ has no member named ‘cdr’
elemlist.c: In function ‘setcar’:
elemlist.c:78:5: error: ‘PyObject’ has no member named ‘car’
elemlist.c:78:5: error: ‘PyObject’ has no member named ‘car’
elemlist.c:78:5: error: ‘PyObject’ has no member named ‘car’
elemlist.c:79:5: error: ‘PyObject’ has no member named ‘car’
elemlist.c: In function ‘setcdr’:
elemlist.c:91:5: error: ‘PyObject’ has no member named ‘cdr’
elemlist.c:91:5: error: ‘PyObject’ has no member named ‘cdr’
elemlist.c:91:5: error: ‘PyObject’ has no member named ‘cdr’
elemlist.c:92:5: error: ‘PyObject’ has no member named ‘car’
elemlist.c: In function ‘initelemlist’:
elemlist.c:107:15: warning: unused variable ‘m’ [-Wunused-variable]
elemlist.c: In function ‘cdr’:
elemlist.c:68:1: warning: control reaches end of non-void function [-Wreturn-type]
elemlist.c: In function ‘car’:
elemlist.c:59:1: warning: control reaches end of non-void function [-Wreturn-type]
error: command 'gcc' failed with exit status 1

-(17.6) - 处理python数据到C中计算并返回。

void
inittotal922(void) {
    (void) Py_InitModule("total922", total922Methods);
}  

# 函数名规则： initModuleName
# Py_InitModule(ModuleNmae, 方法数组)

# setup.py
# ext_modules = [Extension('Modulename', sources = ['sequenceFast_test.c'])]
# 例: ext_modules = [Extension('total922', sources = ['sequenceFast_test.c'])]