Select模式和超时

 1      fd_set rset;
 2         FD_ZERO(&rset);
 3 
 4         int nready;
 5         int maxfd;
 6         int fd_stdin = fileno(stdin);
 7         if(fd_stdin > sock)
 8         {
 9                 maxfd = fd_stdin;
10         }
11         else
12         {
13                 maxfd = sock;
14         }
15 
16         char sendbuf[1024] = { 0 };
17         char recvbuf[1024] = { 0 };
18         while(1)
19         {
20                 FD_SET(fd_stdin,&rset);
21                 FD_SET(sock,&rset);
22                 nready = select(maxfd+1,&rset,NULL,NULL,NULL);
23                 if(nready == -1)
24                         ERR_EXIT("select");
25                 if(nready == 0)
26                         continue;
27 
28                 if(FD_ISSET(sock,&rset))
29                 {
30 
31                         int ret = readline(sock,recvbuf,sizeof(sendbuf));
32                         if(ret == -1)
33                                 ERR_EXIT("readn");
34                         else if(ret ==  0)
35                         {
36                                 printf("server close");
37                                 break;
38                         }
39 
40                         fputs(recvbuf,stdout);
41                         memset(sendbuf,0, sizeof(sendbuf));
42                         memset(recvbuf,0, sizeof(recvbuf));
43                 }
44 
45                 if(FD_ISSET(fd_stdin,&rset))
46                 {
47                         if(fgets(sendbuf,sizeof(sendbuf),stdin) == NULL)
48                                 break;
49                         writen(sock,sendbuf,strlen(sendbuf));
50                 }
51         }
52         close(sock);

View Code

void FD_CLR(int fd,fd_set *set);
int FD_ISSET(int fd,fd_set *set);
void FD_SET(int fd,fd_set *set);
void FD_ZERO(fd_set *set);

select的超时

  1 //读超时
  2 int read_timeout(int fd,unsigned int wait_seconds)
  3 {
  4     int ret = 0;
  5     if(wait_seconds > 0)
  6     {
  7         fd_set read_fdset;
  8         struct timeval timeout;
  9         
 10         FD_ZERO(&read_fdset);
 11         FD_SET(fd,&read_fdset);
 12         
 13         timeout.tv_sec = wait_seconds;
 14         timeout.tv_usec = 0;
 15         do
 16         {
 17             ret = select(fd+1,&read_fdset,NULL,NULL,&timeout);
 18         }while(ret < 0 && errno == EINTR)
 19 
 20         if(ret == 0)
 21         {
 22             ret = -1;
 23             errno = ETIMEDOUT;
 24         }
 25         else if(ret == 1)
 26             ret = 0;
 27     }
 28     return ret;
 29 }
 30 
 31 
 32 //接收超时
 33 int accept_timeout(int fd,struct sockaddr_in *addr,unsigned int wait_seconds)
 34 {
 35     int ret;
 36     socklen_t addrlen = sizeof(struct sockaddr_in);
 37     
 38     if(wait_seconds > 0)
 39     {
 40         fd_set accept_fdset;
 41         struct timeval timeout;
 42         FD_ZERO(&accept_fdset);
 43         FD_SET(fd,&accept_fdset);
 44         timeout.tv_sec = wait_seconds;
 45         timeout.tv_usec = 0;
 46         do
 47         {
 48             ret = select(fd+1,&accept_fdset,NULL,NULL,&timeout);
 49         }while(ret < 0 && errno == EINTR)
 50         
 51         if(ret == -1)
 52             return -1;
 53         else if(ret == 0)
 54         {
 55             errno = ETIMEDOUT;
 56             return -1;
 57         }
 58     }
 59     if(addr != NULL)
 60         ret = accept(fd,(struct sockaddr*)addr,&addrlen);
 61     else
 62         ret = accept(fd,NULL,NULL);
 63     if(ret == -1)
 64         ERR_EXIT("accept");
 65     return ret;
 66 }
 67 
 68 void activate_nonblock(int fd)
 69 {
 70     int ret;
 71     int flags = fcntl(fd,F_GETFL);
 72     if(flags == -1)
 73         ERR_EXIT("fcntl");
 74     flags |= O_NONBLOCK;
 75     ret = fcntl(fd,F_SETFL,flags);
 76     if(ret == -1)
 77         ERR_EXIT("fcntl");
 78 }
 79 
 80 void deactivate_nonblock(int fd)
 81 {
 82     int ret;
 83     int flags = fcntl(fd,F_GETFL);
 84     if(flags == -1)
 85         ERR_EXIT("fcntl");
 86     flags &~ O_NONBLOCK;
 87     ret = fcntl(fd,F_SETFL,flags);
 88     if(ret == -1)
 89         ERR_EXIT("fcntl");
 90 }
 91 
 92 //连接超时
 93 int connect_timeout(int fd,struct sockaddr_in *addr, unsigned int wait_seconds)
 94 {
 95     int ret;
 96     socklen_t addrlen = sizeof(struct sockaddr_in);
 97 
 98     if(wait_seconds > 0)
 99         activat_nonblock(fd);
100     
101     ret = connect(fd,(struct sockaddr*)addr,addrlen);
102     if(ret < 0 && errno == EINPROGRESS)
103     {
104         fd_set connect_fdset;
105         struct timeval timeout;
106         FD_ZERO(&connect_fdset);
107         FD_SET(fd,&connect_fdset);
108         timeout.tv_sec = wait_seconds;
109         timeout.tv_usec = 0;
110         do
111         {
112             ret = select(fd+1,NULL,&connect_fdset,NULL,&timeout);
113         }while(ret < 0 && errno == EINTR)
114         if(ret == 0)
115         {
116             ret = -1;
117             errno = ETIMEDOUT;
118         }
119         else if(ret < 0)
120             return -1;
121         else if(ret == 1)
122         {
123             int err;
124             socklen_t socklen = sizeof(err);
125             int sockoptret = getsockopt(fd,SOL_SOCKET,SO_ERROR,&err,&socklen);
126             if(sockoptret == -1)
127             {
128                 return -1;
129             }
130             if(err == 0)
131                 ret = 0;
132             else
133             {
134                 errno = err;
135                 ret = -1;
136             }
137         }
138     }
139 
140     if(wait_seconds > 0)
141     {
142         deactivate_nonblock(fd);
143     }
144     return ret;
145 }

View Code

作者：长风 Email：844064492@qq.com QQ群：607717453 Git：https://github.com/zhaohu19910409Dz 开源项目：https://github.com/OriginMEK/MEK 本文版权归作者和博客园共有，欢迎转载，但未经作者同意必须保留此段声明，且在文章页面明显位置给出原文连接，否则保留追究法律责任的权利. 感谢您的阅读。如果觉得有用的就请各位大神高抬贵手“推荐一下”吧！你的精神支持是博主强大的写作动力。如果觉得我的博客有意思，欢迎点击首页左上角的“+加关注”按钮关注我！

相关阅读:
Flink 源码阅读环境搭建并调试 Flink-Clients 模块
 阅读 Flink 源码前必会的知识 SPI 和 Classloader
如何 debug hive 源码，知其然知其所以然
 Flink SQL 核心概念剖析与编程案例实战
 Apache Flink 如何正确处理实时计算场景中的乱序数据
 Flink 编程接口
 Flink JobManager 和 TaskManager 原理
 一文带你了解 Flink 的基本组件栈
 flink有什么优势值得大家这么热衷
 实时计算数据架构的演变
原文地址：https://www.cnblogs.com/zhaohu/p/8972315.html