在学习UNP卷一时候，书上的第一道例子：时间获取服务器程序，代码如下：
daytimetcpsrv.c：
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <fcntl.h>
#define SA struct sockaddr
#define MAXLINE 1024
int main( void )
{
int listenfd, connfd;
struct sockaddr_in servaddr;
char buff[ MAXLINE ];
time_t ticks;
pid_t pid;
listenfd = socket( AF_INET, SOCK_STREAM, 0 );
bzero( &servaddr, sizeof( servaddr ) );
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
servaddr.sin_port = htonl(13);
bind(listenfd, ( SA * )&servaddr, sizeof(servaddr));
listen( listenfd, 5 );
for( ; ; ){
connfd = accept( listenfd, ( SA * )NULL, NULL);
pid = fork();
if ( 0 == pid ){
ticks = time( NULL );
snprintf(buff, sizeof(buff), "%.24s\r\n", ctime(&ticks));
write( connfd, buff, strlen(buff));
}
if ( waitpid(pid, NULL,0 ) != pid ){
printf("waitpid error");
exit(1);
}
close( connfd );
}
return 0;
}
而客户端为：
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdlib.h>
#define SA struct sockaddr
#define MAXLINE 1024
int main( int argc, char **argv )
{
int sockfd, n;
char recvline[ MAXLINE + 1 ];
struct sockaddr_in servaddr;
if ( argc != 2 ){
printf("usage:a.out <IPaddress>");
exit(1);
}
if ( ( sockfd = socket( AF_INET, SOCK_STREAM, 0 ) ) < 0 ){
printf("socket error\n");
exit(1);
}
bzero( &servaddr, sizeof( servaddr ) );
servaddr.sin_family = AF_INET;
servaddr.sin_port = htons( 13 );
servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");
/*
if ( inet_pton( AF_INET, argv[ 1 ], &servaddr.sin_addr ) <= 0 ){
printf("inet_pton error for %s", argv[1]);
exit(1);
}
*/
if ( connect( sockfd, ( SA * )&servaddr, sizeof( servaddr ) ) < 0 ){
printf("connect error\n");
exit(1);
}
while ( ( n = read( sockfd, recvline, MAXLINE )) > 0){
recvline[n] = 0;
if (fputs(recvline, stdout) == EOF){
printf("fputs error\n");
exit(1);
}
}
if (n < 0){
printf("read error\n");
exit(1);
}
exit(0);
}
程序的运行结果是：客户端一直提示：connect失败。
我不知道为什么会connect失败？
运行环境是ubuntu，用两个终端在本机上分别运行服务端和客户端。
