Linux C编程---网络编程

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#include <arpa/inet.h>
int inet_pton(int family,const char * strptr,void * addrptr);
 返回：1－－－成功　0－－－输入不是有效的表达格式　-1－－－失败 
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#include <arpa/inet.h> 　 
const char * inet_ntop(int family,const void *
addrptr,char * strptr,size_t len); 　 
　　 返回：指向结果的指针－－－成功　　　NULL－－－失败 
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#include <unistd.h> 　 
pid_t fock(void);
返回：在子进程中为0，在父进程中为子进程ID　　　-1－－－失败 
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/* client.c */
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
int main(int argc,char *argv[]) {
int sockfd,numbytes;
char buf[100];
struct hostent *he;
struct sockaddr_in their_addr;
int i = 0;
//将基本名字和地址转换
he = gethostbyname(argv[1]);
//建立一个TCP套接口
if((sockfd = socket(AF_INET,SOCK_STREAM,0))==-1) {
perror("socket");
exit(1);
}
//初始化结构体，连接到服务器的2323端口
their_addr.sin_family = AF_INET;
their_addr.sin_port = htons(2323);
their_addr.sin_addr = *((struct in_addr *)he->h_addr);
bzero(&(their_addr.sin_zero),8);
//和服务器建立连接
if(connect(sockfd,(struct sockaddr *)&their_addr,
sizeof(struct sockaddr))
==-1){
perror("connect");
exit(1);
}
//向服务器发送字符串"hello!"
if(send(sockfd,"hello!",6,0)==-1) {
perror("send");
exit(1);
}
//接受从服务器返回的信息
if((numbytes = recv(sockfd,buf,100,0))==-1) {
perror("recv");
exit(1);
}
buf[numbytes] = '';
printf("result:%s",buf);
close(sockfd);
return 0;
}
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/* server.c */
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/wait.h>
main() {
int sockfd,new_fd;
struct sockaddr_in my_addr;
struct sockaddr_in their_addr;
int sin_size;
//建立TCP套接口
if((sockfd = socket(AF_INET,SOCK_STREAM,0))==-1) {
perror("socket");
exit(1);
}
//初始化结构体，并绑定2323端口
my_addr.sin_family = AF_INET;
my_addr.sin_port = htons(2323);
my_addr.sin_addr.s_addr = INADDR_ANY;
bzero(&(my_addr.sin_zero),8);
//绑定套接口
if(bind(sockfd,(struct sockaddr *)&my_addr,sizeof(struct 
sockaddr))==-1)
{
perror("bind");
exit(1);
}
//创建监听套接口
if(listen(sockfd,10)==-1) {
perror("listen");
exit(1);
}
//等待连接
while(1) {
sin_size = sizeof(struct sockaddr_in);
perror("server is run");
//如果建立连接，将产生一个全新的套接字
if((new_fd = accept(sockfd,(struct sockaddr *)
&their_addr,&sin_size))==-1)
{
perror("accept");
exit(1);
}
//生成一个子进程来完成和客户端的会话，父进程继续监听
if(!fork()) {
//读取客户端发来的信息
if((numbytes = recv(new_fd,buff,strlen(buff),0))==-1)
{
perror("recv");
exit(1);
}
printf("%s",buff);
//将从客户端接收到的信息再发回客户端
if(send(new_fd,buff,strlen(buff),0)==-1)
perror("send");
close(new_fd);
exit(0);
}
close(new_fd);
}
close(sockfd);
}
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