VisuaGDB 编译、调试libev

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由于在Linux下阅读、调试libev源码过于复杂繁琐，需要为vim或emacs做配置一堆配置，才稍微好些，但是操作起来十分困难，花费大量的时间，影响阅读和理解libev的速度。所以使用VisualGDB编译、调试libev。

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编译环境

• Visual gdb 5.0
• VS2013
• Ubuntu 16.04 server 虚拟机 安装gcc、g++、gdb、open-ssh
• win 7操作系统

编译步骤

• 下载libev到Ubuntu Linux
  地址：https://github.com/quartzjer/libev

• 在Linux下编译libev
  1.执行./configure 命令
  
  2.执行make命令。从编译输出可以看到执行make的时候，只是编译了ev.c、event.c 两个文件
  

• 在window中创建Visual gdb项目
  参考网址：http://blog.csdn.net/wu936754331/article/details/49305377

• 拷贝libev中的文件到Visual gdb项目中
  将.c、.h文件拷贝到Visual gdb项目中
  
• 添加libev文件并编译运行
  只添加ev.c、event.c和头文件，并创建main.c文件，并粘贴一下demo代码，然后编译运行。如果添加了其他的.c文件，编译会报错，因为ev_epoll.c ev_kqueue.c ev_poll.c ev_port.c ev_select.c ev_win32.c这个几个源文件没有.h文件的，它们被ev.c event.c直接include 插入到源码中，若再次添加就会产生编译报错。如果想更好地阅读源码，直接将源码插入到include .c文件处
  

// a single header file is required

#include <stdio.h> // for puts
#include <stdio.h>
#include <netinet/in.h>
#include <errno.h>
#include "ev.h"
#define MAXLEN 1023
#define PORT 1200
#define ADDR_IP "192.168.1.112"


int socket_init();
void accept_callback(struct ev_loop *loop, ev_io *w, int revents);
void recv_callback(struct ev_loop *loop, ev_io *w, int revents);
void write_callback(struct ev_loop *loop, ev_io *w, int revents);


int main(int argc, char** argv)
{
    int listen;
    ev_io ev_io_watcher;
    listen = socket_init();
    struct ev_loop *loop = ev_loop_new(EVBACKEND_EPOLL);
    ev_io_init(&ev_io_watcher, accept_callback, listen, EV_READ);
    ev_io_start(loop, &ev_io_watcher);
    ev_loop(loop, 0);
    ev_loop_destroy(loop);
    return 0;

}

int socket_init()
{
    struct sockaddr_in my_addr;
    int listener;
    if ((listener = socket(AF_INET, SOCK_STREAM, 0)) == -1)
    {
        perror("socket");
        exit(1);
    }
    else
    {
        printf("SOCKET CREATE SUCCESS!\n");
    }
    //setnonblocking(listener);
    int so_reuseaddr = 1;
    setsockopt(listener, SOL_SOCKET, SO_REUSEADDR, &so_reuseaddr, sizeof(so_reuseaddr));
    bzero(&my_addr, sizeof(my_addr));
    my_addr.sin_family = PF_INET;
    my_addr.sin_port = htons(PORT);
    my_addr.sin_addr.s_addr = inet_addr(ADDR_IP);

    if (bind(listener, (struct sockaddr *) &my_addr, sizeof(struct sockaddr)) == -1)
    {
        perror("bind error!\n");
        exit(1);
    }
    else
    {
        printf("IP BIND SUCCESS,IP:%s\n", ADDR_IP);
    }

    if (listen(listener, 1024) == -1)
    {
        perror("listen error!\n");
        exit(1);
    }
    else
    {
        printf("LISTEN SUCCESS,PORT:%d\n", PORT);
    }
    return listener;
}

void accept_callback(struct ev_loop *loop, ev_io *w, int revents)
{
    int newfd;
    struct sockaddr_in sin;
    socklen_t addrlen = sizeof(struct sockaddr);
    ev_io* accept_watcher = malloc(sizeof(ev_io));
    while ((newfd = accept(w->fd, (struct sockaddr *)&sin, &addrlen)) < 0)
    {
        if (errno == EAGAIN || errno == EWOULDBLOCK)
        {
            //these are transient, so don't log anything.
            continue;
        }
        else
        {
            printf("accept error.[%s]\n", strerror(errno));
            break;
        }
    }
    ev_io_init(accept_watcher, recv_callback, newfd, EV_READ);
    ev_io_start(loop, accept_watcher);
    printf("accept callback : fd :%d\n", accept_watcher->fd);

}

void recv_callback(struct ev_loop *loop, ev_io *w, int revents)
{
    char buffer[1024] = { 0 };
    int ret = 0;
    //ev_io write_event;
loop:
    ret = recv(w->fd, buffer, MAXLEN, 0);
    if (ret > 0)
    {
        printf("recv message :%s  \n", buffer);

    }
    else if (ret == 0)
    {
        printf("remote socket closed!socket fd: %d\n", w->fd);
        close(w->fd);
        ev_io_stop(loop, w);
        free(w);
        return;
    }
    else
    {
        if (errno == EAGAIN || errno == EWOULDBLOCK)
        {
            goto loop;
        }
        else
        {
            printf("ret :%d ,close socket fd : %d\n", ret, w->fd);
            close(w->fd);
            ev_io_stop(loop, w);
            free(w);
            return;
        }
    }
    int fd = w->fd;
    ev_io_stop(loop, w);
    ev_io_init(w, write_callback, fd, EV_WRITE);
    ev_io_start(loop, w);
    printf("socket fd : %d, turn read 2 write loop! ", fd);

}


void write_callback(struct ev_loop *loop, ev_io *w, int revents)
{
    char buffer[1024] = { 0 };
    //ev_io read_event;
    snprintf(buffer, 1023, "this is a libev server!\n");
    write(w->fd, buffer, strlen(buffer), 0);
    int fd = w->fd;
    ev_io_stop(loop, w);
    ev_io_init(w, recv_callback, fd, EV_READ);
    ev_io_start(loop, w);
}