ubuntu下安装Libevent，并通过QT测试

朴灿烈づ我的快乐病毒、 2022-05-30 01:09 238阅读 0赞

1、官网下载最新的[Libevent-2.022][]  
2、解压安装包，并进入文件包

tar -zxvf libevent-2.0.22-stable.tzr.gz  
    cd libevent-2.0.22-stable

3、配置编译并安装

1、./configure --prefix=/usr   #如果前面有CFLAGS=-DUSE_DEBUG则编译成bug版本。
    2、make  
    3、sudo make install

4、 验证安装正确

ls -al /usr/lib |grep libevent

显示很多文件，那么就安装正确  
5、QT下测试要点

> QT新键普通工程，要点在与.pro对应文件里面加入Libevent的库，这样才可以链接成功。

LIBS += -levent
    LIBS += -levent_core
    LIBS += -levent_extra

测试：  
client

#include <unistd.h>
    #include <stdio.h>
    #include <fcntl.h>
    #include <netdb.h>
    #include <sys/socket.h>
    #include <stdlib.h>
    #include <string.h>
    #include <arpa/inet.h>
    #define cerror(str) do{perror(str); exit(EXIT_FAILURE); }while(0)
    
    static int port;
    static char addr[256];
    static int nlen;
    static char msg[]="hello\n";
    int main(int argc, char*argv[])
    {
    
        int fd;
        struct sockaddr_in sin;
    
        memset(&sin, 0, sizeof(sin));
        sin.sin_family = AF_INET;
    
        if(argc<3)
        {
            port = 8888;
        }else
        {
            port = atoi(argv[2]);
        }
    
        sin.sin_port = htons(port);
    
        if(argc<2)
        {
            strcpy(addr, argv[1]);
            if (inet_pton(AF_INET, addr, &(sin.sin_addr) )<0)
            {
                 struct hostent *psh;
                 psh=gethostbyname(addr);
                 if(psh!=NULL)
                    inet_pton(AF_INET, psh->h_addr, &(sin.sin_addr) );
                 else
                    cerror("inet_pton");
            }
        }
    
        if((fd=socket(AF_INET, SOCK_STREAM, 0))<0)
            cerror("socket");
    
        if(connect(fd, (struct sockaddr*)&sin, sizeof(sin))<0 )
            cerror("sonnect");
    
        if( (nlen = write(fd,msg, strlen(msg)))<0 )
            cerror("write");
    
        if( (nlen = read(fd,msg, strlen(msg)))<0 )
            cerror("read");
        msg[nlen]='\0';
        printf("msg: %s\n", msg);
        return 0;
    }

server：

#include <sys/socket.h>
    #include <sys/types.h>
    #include <netinet/in.h>
    #include <stdio.h>
    #include <string.h>
    #include <event.h>
    #include <stdlib.h>
    #include <unistd.h>
    
    #define PORT 25341
    #define BACKLOG 5
    #define MEM_SIZE 1024
    
    struct event_base* base;
    struct sock_ev
    {
        struct event* read_ev;
        struct event* write_ev;
        char* buffer;
    };
    
    void release_sock_event(struct sock_ev* ev)
    {
        event_del(ev->read_ev);
        free(ev->read_ev);
        free(ev->write_ev);
        free(ev->buffer);
        free(ev);
    }
    
    void on_write(int sock, short event, void* arg)
    {
        char* buffer = (char*)arg;
        send(sock, buffer, strlen(buffer), 0);
    
        free(buffer);
    }
    
    void on_read(int sock, short event, void* arg)
    {
        struct event* write_ev;
        int size;
        struct sock_ev* ev = (struct sock_ev*)arg;
        ev->buffer = (char*)malloc(MEM_SIZE);
        bzero(ev->buffer, MEM_SIZE);
        size = recv(sock, ev->buffer, MEM_SIZE, 0);
        printf("receive data:%s, size:%d\n", ev->buffer, size);
        if (size == 0)
        {
            release_sock_event(ev);
            close(sock);
            return;
        }
        event_set(ev->write_ev, sock, EV_WRITE, on_write, ev->buffer);
        event_base_set(base, ev->write_ev);
        event_add(ev->write_ev, NULL);
    }
    
    void on_accept(int sock, short event, void* arg)
    {
        struct sockaddr_in cli_addr;
        int newfd;
        socklen_t sin_size;
        struct sock_ev* ev = (struct sock_ev*)malloc(sizeof(struct sock_ev));
        ev->read_ev = (struct event*)malloc(sizeof(struct event));
        ev->write_ev = (struct event*)malloc(sizeof(struct event));
        sin_size = sizeof(struct sockaddr_in);
        newfd = accept(sock, (struct sockaddr *) &cli_addr, &sin_size);
        event_set(ev->read_ev, newfd, EV_READ|EV_PERSIST, on_read, ev);
        event_base_set(base, ev->read_ev);
        event_add(ev->read_ev, NULL);
    }
    
    int main(int argc, char* argv[])
    {
        struct sockaddr_in my_addr;
        int sock;
    
        sock = socket(AF_INET, SOCK_STREAM, 0);
        int yes = 1;
        setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int));
        memset(&my_addr, 0, sizeof(my_addr));
        my_addr.sin_family = AF_INET;
        my_addr.sin_port = htons(PORT);
        my_addr.sin_addr.s_addr = INADDR_ANY;
        bind(sock, (struct sockaddr*)&my_addr, sizeof(struct sockaddr));
        listen(sock, BACKLOG);
    
        struct event listen_ev;
        base = event_base_new();
        event_set(&listen_ev, sock, EV_READ|EV_PERSIST, on_accept, NULL);
        event_base_set(base, &listen_ev);
        event_add(&listen_ev, NULL);
        event_base_dispatch(base);
    
        return 0;
    }

![这里写图片描述][SouthEast]

[Libevent-2.022]: https://github.com/libevent/libevent/releases/download/release-2.0.22-stable/libevent-2.0.22-stable.tar.gz
[SouthEast]: /images/20220530/86057bdc486746149d6f65f6955f4d6d.png