Linux开发部分代码练习

#include<stdio.h>
#include<unistd.h>
#define BUF_SIZE 100

int main(int argc, char *argv[])
{
int fds[2];
int fds2[2];
char str[] = "who are you?";
char str2[] = "Thank you from your message";
char buf[BUF_SIZE];
pid_t pid;
pipe(fds);
pipe(fds2);
pid  = fork();

if(0 == pid)
{
write(fds[1],str,sizeof(str));
read(fds2[0],buf,sizeof(buf));
printf("Child proc output:%s\n",buf);
}
else
{
read(fds[0],buf,sizeof(buf));
printf("parent proc output:%s\n",buf);
write(fds2[1],str2,sizeof(str2));
sleep(3);
}
return 0;
}

#include <stdio.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/select.h>

#define   BUF_SIZE 30

int main(int argc, char*argv[])
{
fd_set reads,temps;
int result,str_len;
char buf[BUF_SIZE];

FD_ZERO(&reads);
FD_SET(0,&reads);
struct timeval timeout;
//timeout.tv_sec = 5;
//timeout.tv_usec = 5000;

while (1)
{
temps = reads;
timeout.tv_sec = 5;
timeout.tv_usec = 0;

result = select(1,&temps,0,0,&timeout);
if(-1 == result)
{
puts("select() error");
break;
}
else if(0 == result)
{
puts("time-out");
}
else
{
if(FD_ISSET(0,&temps))
{
str_len = read(0,buf,BUF_SIZE);
buf[str_len] = 0;
printf("message from console:%s",buf);
}
}
}

return 0;
}

#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 *message);

int main(int argc, char const *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(AF_INET,SOCK_STREAM,0);
memset(&serv_sock,0,sizeof(serv_sock));
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(0 == fd_num)
{
continue;
}

for(i = 0;i < fd_max +1; i++)
{
if(FD_ISSET(i,&cpy_reads))
{
if(i == serv_sock) // connetion 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("close client:%d\n",i);
}
else
{
write(i,buf,str_len);
}
}
}
}
}
close(serv_sock);
return 0;
}

void error_handling(char *buf)
{
fputs(buf,stderr);
fputc('\n',stderr);
exit(1);
}