用C语言扩展Python接口



#假设模块名字是FMBus，并且被保存为fmbusmodule.c
#include"Python.h"
#include"structmember.h"    //Python\Python36\include  路径下
#include"object.h"   //Python\Python36\include 路径下

........
//定义对象
typedef struct {
 PyObject_HEAD

 int fd;  /* open file descriptor: /dev/FMdev1? */
 int addr; /* current address */
 int value; /* address and value pairs*/
 int pec; /* !0 => Packet Error Codes enabled */
} FMBus;

//定义各个回调函数，用于填充PyTypeObject

static PyObject *FMBus_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
 FMBus *self;

 // 1，alloc memory to self;
 // 2，init member value of self-
 self->fd = xx;
 self->addr = 0x10000;
 self->value = 0;

 return (PyObject *)self;
}

static int FMBus_init(FMBus *self, PyObject *args, PyObject *kwds)
{
 int bus = -1;

 static char *kwlist[] = {"bus", NULL};

 if (!PyArg_ParseTupleAndKeywords(args, kwds, "|i:__init__",
   kwlist, &bus))
  return -1;

 if (bus >= 0) {
  FMBus_open(self, args, kwds);
  if (PyErr_Occurred())
   return -1;
 }

 return 0;
}

//定义和填充 PyTypeObject 结构体

static PyTypeObject FMBus_type=
{
 PyVarObject_HEAD_INIT(NULL, 0)
 "FMBus",   /* tp_name */
 sizeof(FMBus),   /* tp_basicsize */
 0,    /* tp_itemsize */
 (destructor)FMBus_dealloc, /* tp_dealloc */
 0,    /* tp_print */
 0,    /* tp_getattr */
 0,    /* tp_setattr */
 0,    /* tp_compare */
 0,    /* tp_repr */
 0,    /* tp_as_number */
 0,    /* tp_as_sequence */
 0,    /* tp_as_mapping */
 0,    /* tp_hash */
 0,    /* tp_call */
 0,    /* tp_str */
 0,    /* tp_getattro */
 0,    /* tp_setattro */
 0,    /* tp_as_buffer */
 Py_TPFLAGS_DEFAULT,  /* tp_flags */
 FMBus_type_doc,   /* tp_doc */
 0,    /* tp_traverse */
 0,    /* tp_clear */
 0,    /* tp_richcompare */
 0,    /* tp_weaklistoffset */
 0,    /* tp_iter */
 0,    /* tp_iternext */
 FMBus_methods,   /* tp_methods */
 0,    /* tp_members */
 FMBus_getset,   /* tp_getset */
 0,    /* tp_base */
 0,    /* tp_dict */
 0,    /* tp_descr_get */
 0,    /* tp_descr_set */
 0,    /* tp_dictoffset */
 (initproc)FMBus_init,  /* tp_init */
 0,    /* tp_alloc */
 FMBus_new,   /* tp_new */
};

//定义和填充 PyMethodDef 结构体
static PyMethodDef FMBus_methods[] = {
 {"open", (PyCFunction)FMBus_open, METH_VARARGS | METH_KEYWORDS,
  FMBus_open_doc},
 {"close", (PyCFunction)FMBus_close, METH_NOARGS,
  FMBus_close_doc},
 {"read_byte", (PyCFunction)FMBus_read_byte, METH_VARARGS,
  SMBus_read_byte_doc},
 {"write_byte", (PyCFunction)FMBus_write_byte, METH_VARARGS,
  SMBus_write_byte_doc}
 
 。。。。。。
 
};
//定义和填充PyModuleDef

static struct PyModuleDef SMBusModule = {
 PyModuleDef_HEAD_INIT,
 "FMBus",   /* m_name */
 FMBus_module_doc,    /* m_doc */
 -1,    /* m_size */
 NULL,    /* m_methods */
 NULL,    /* m_reload */
 NULL,    /* m_traverse */
 NULL,    /* m_clear */
 NULL,    /* m_free */
};

//最后，初始化模块

void PyInit_fmbus(void)
{
 PyObject* m;

 if (PyType_Ready(&FMBus_type) < 0)
  return(NULL);

 m = PyModule_Create(&FMBusModule);

 if (m == NULL)
  return (NULL);

 Py_INCREF(&FMBus_type);
 PyModule_AddObject(m, "FMBus", (PyObject *)&FMBus_type);

 return (m);
}