设置socket接收和发送超时的一种方式

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <strings.h>
#include <string.h>
#include <thread>

#include <unistd.h>
extern char *optarg;
extern int optind, opterr, optopt;

#include <getopt.h>

#define LOG_ERROR my_printf


int my_printf(char *fmt, ...)
{
    char buffer[1024];
    va_list argptr;
    int length = 0;
    
    va_start(argptr, fmt);
    length = vsnprintf(buffer,1024 ,fmt, argptr);
    va_end(argptr);
    
    printf("%s\n", buffer);
    
    return (length + 1);
}


int start_client(const char *host, int port, const char *local_host = NULL)
{
    int client_socket = socket(AF_INET,SOCK_STREAM,0);
    
    if( client_socket < 0)
    {
        LOG_ERROR("Create socket failed, errno %d", errno);
        return -1;
    }
    
    //设置一个socket地址结构server_addr,代表服务器的internet地址, 端口
    struct sockaddr_in server_addr;
    bzero(&server_addr,sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    if(inet_aton(host,&server_addr.sin_addr) == 0)
    {
        LOG_ERROR("Server address inet_aton failed, errno %d!", errno);
        return -1;
    }
    
    if (local_host != NULL)
    {
        sockaddr_in client_addr;
        client_addr.sin_family = AF_INET;
        client_addr.sin_addr.s_addr = inet_addr(local_host);
        
        
        if (bind(client_socket,(struct sockaddr*)&client_addr, sizeof(client_addr)) == -1)
        {
            LOG_ERROR("\nBind client failed, local_host %s, errno %d, %s\n",
                      local_host, errno, strerror(errno));
            close(client_socket);
            return -1;
        }
        
    }
    
    server_addr.sin_port = htons(port);
    socklen_t server_addr_length = sizeof(server_addr);
    
    //向服务器发起连接,连接成功后client_socket代表了客户机和服务器的一个socket连接
    if(connect(client_socket,(struct sockaddr*)&server_addr, server_addr_length) < 0)
    {
        LOG_ERROR("Connect to %s:%d failed! error %d, %s", host, port, errno, strerror(errno));
        close(client_socket);
        
        return -1;
    }
    
    // write(client_socket, "Hello Server", strlen("Hello Server"));
    
    return client_socket;
}


int main()
{
    int sock = 0;
    struct timeval timeout = {3,0};
    int tm = 0;
    int res = 0;
    char buf[1024];
    
    sock = start_client("127.0.0.1", 5050);
    
    setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout, sizeof(struct timeval));

    tm = time(0);
    res = read(sock, buf, 1024);
    fprintf(stderr, "Read timeout %d\n", time(0) - tm);
    
    return 0;
}