基于select机制的Socket服务端
1、首先附一下李慧芹关于select机制的讲解:高级IO-select_哔哩哔哩_bilibili 高级IO-select实例_哔哩哔哩_bilibili
2、基于Select机制的服务端代码
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/select.h>
#define BUF_SIZE 100
void error_handling(char *buf);
int main(int argc, char *argv[])
{
int serv_sock, clnt_sock;
struct sockaddr_in serv_adr, clnt_adr;
struct timeval timeout;
fd_set reads, cpy_reads;
socklen_t adr_sz;
int fd_max, str_len, fd_num, i;
char buf[BUF_SIZE];
if(argc!=2) {
printf("Usage : %s <port>\n", argv[0]);
exit(1);
}
serv_sock=socket(PF_INET, SOCK_STREAM, 0);
memset(&serv_adr, 0, sizeof(serv_adr));
serv_adr.sin_family=AF_INET;
serv_adr.sin_addr.s_addr=htonl(INADDR_ANY);
serv_adr.sin_port=htons(atoi(argv[1]));
if(bind(serv_sock, (struct sockaddr*) &serv_adr, sizeof(serv_adr))==-1)
error_handling("bind() error");
if(listen(serv_sock, 5)==-1)
error_handling("listen() error");
FD_ZERO(&reads);
FD_SET(serv_sock, &reads);
fd_max=serv_sock;
while(1)
{
cpy_reads=reads;
timeout.tv_sec=5;
timeout.tv_usec=5000;
if((fd_num=select(fd_max+1, &cpy_reads, 0, 0, &timeout))==-1)
break;
if(fd_num==0)
continue;
for(i=0; i<fd_max+1; i++)
{
if(FD_ISSET(i, &cpy_reads))
{
if(i==serv_sock) // connection request!
{
adr_sz=sizeof(clnt_adr);
clnt_sock=
accept(serv_sock, (struct sockaddr*)&clnt_adr, &adr_sz);
FD_SET(clnt_sock, &reads);
if(fd_max<clnt_sock)
fd_max=clnt_sock;
printf("connected client: %d \n", clnt_sock);
}
else // read message!
{
str_len=read(i, buf, BUF_SIZE);
if(str_len==0) // close request!
{
FD_CLR(i, &reads);
close(i);
printf("closed client: %d \n", i);
}
else
{
write(i, buf, str_len); // echo!
}
}
}
}
}
close(serv_sock);
return 0;
}
void error_handling(char *buf)
{
fputs(buf, stderr);
fputc('\n', stderr);
exit(1);
}