python和C语言混合编程实例


            最近为了测试网速情况怎么样，由于部分业务服务器需要关闭icmp，这样的话采用普通的ping就无法适应我的需求，于是自己简单的写了一个基于tcp端口的ping的程序，由于c执行效率比较的不错，但是开发效率低下，而python是开发效率高，但是执行效率不如C，由于需要大规模的使用，于是用C实现核心部分的代码，并把这部分实现成一个python的模块，由python调用c的模块，下面就贴代码吧

复制代码 代码如下:/* tcpportping.c */#include <Python.h>#include <string.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <netdb.h>#include <sys/time.h>/* count time functions */static double mytime(void){    struct timeval tv;    if (gettimeofday(&tv, NULL) == -1)        return 0.0;    return (double)tv.tv_usec + (double)tv.tv_sec * 1000000;}static PyObject *                                 /* returns object */tcpping(PyObject *self, PyObject *args ){    struct  sockaddr_in addr;    struct  hostent *hp;    double  time;    char    *host = NULL;    int     fd;    int     port, timeout;    if (!PyArg_ParseTuple(args, "sii", &host, &port, &timeout))  /* convert Python -> C */        return NULL;                              /* null=raise exception */    if ((fd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {        return Py_BuildValue("d", -1.0);        /* convert C -> Python */    }    bzero((char *)&addr, sizeof(addr));    if ((hp = gethostbyname(host)) == NULL) {        return Py_BuildValue("d", -2.0);        /* convert C -> Python */    }    bcopy(hp->h_addr, &addr.sin_addr, hp->h_length);    addr.sin_family = AF_INET;    addr.sin_port = htons(port);    struct timeval tv;    tv.tv_sec = 0;    tv.tv_usec = timeout * 1000;    double stime = mytime();    if (connect(fd, (struct sockaddr*)&addr, sizeof(addr)) < 0) {        return Py_BuildValue("d", -3.0);        /* convert C -> Python */    }    fd_set read, write;    FD_ZERO(&read);    FD_ZERO(&write);    FD_SET(fd, &read);    FD_SET(fd, &write);    if (select(fd + 1, &read, &write, NULL, &tv) == 0) {        close(fd);        return Py_BuildValue("d", -4.0);        /* convert C -> Python */    }    double etime = mytime();    time = etime - stime;    if (!FD_ISSET(fd, &read) && !FD_ISSET(fd, &write)) {        close(fd);        return Py_BuildValue("d", -4.0);        /* convert C -> Python */    }    close(fd);    return Py_BuildValue("d", time/1000);        /* convert C -> Python */}/* registration table  */static struct PyMethodDef portping_methods[] = {    {"tcpping", tcpping, METH_VARARGS},       /* method name, C func ptr, always-tuple */    {NULL, NULL}                   /* end of table marker */};/* module initializer */void inittcpportping( )                       /* called on first import */{                                      /* name matters if loaded dynamically */    (void) Py_InitModule("tcpportping", portping_methods);   /* mod name, table ptr */}

编译成python模块复制代码 代码如下:gcc tcpportping.c  -I/usr/include/python2.4 -shared -L/usr/bin -fpic -lpython2.4 -o tcpportping.so

下面是python调用c模块的代码：复制代码 代码如下:#!/usr/bin/env pythonimport tcpportpingimport timei = 0while i < 5:    t = tcpportping.tcpping('www.baidu.com', 80, 1000)    if t < 0:        print "time out"    else:        print t    time.sleep(0.5)    i += 1执行python代码就可以实现端口ping的结果，从测试的情况来看，该程序执行的结果跟普通的ping几乎没有什么差别。