Linux socket编程入门（1）

server.c和client.c的头文件

<sys/types.h>

<sys/socket.h>

<unistd.h>

<string.h>

<netinet.h>

<stdio.h>

<stdlib.h>

 

server.c的代码如下

-----------------------------------------------------------------------------------------------#defineBUF_SIZE10int main(){int s_socketfd;int s_len;struct sockaddr_in s_address;s_socketfd=socket(AF_INET,SOCK_STREAM,0);s_address.sin_family=AF_INET;s_address.sin_addr.s_addr=htonl(INADDR_ANY);s_address.sin_port=htons(9374);s_len=sizeof(s_address);bind(s_socketfd,(struct sockaddr*)&s_address,s_len);listen(s_socketfd,2);while(1){printf("Server Ready/n");int c_socketfd;int c_len;struct sockaddr_in c_address;char buffer[BUF_SIZE];int readnum=0;memset(buffer,0,BUF_SIZE);c_len=sizeof(c_address);c_socketfd=accept(s_socketfd,(struct sockaddr*)&c_address,&c_len);printf("from client:");while((readnum=read(c_socketfd,buffer,BUF_SIZE))>0){printf("%s",buffer);memset(buffer,0,BUF_SIZE);}printf("/n");close(c_socketfd);}return 0;} 

client.c的代码如下：

#defineBUF_SIZE30int main(int argc,char *args[]){int socketfd;int len;struct sockaddr_in address;char buffer[BUF_SIZE];int flag;memset(buffer,0,BUF_SIZE);if(argc!=2){perror("arguments error!/n");exit(1);}else{strcpy(buffer,args[1]);}socketfd=socket(AF_INET,SOCK_STREAM,0);address.sin_family=AF_INET;address.sin_addr.s_addr=inet_addr("127.0.0.1");//服务器IP地址address.sin_port=htons(9374);//服务器端口len=sizeof(address);flag=connect(socketfd,(struct sockaddr*)&address,len);if(flag==-1){perror("connect error");exit(1);}write(socketfd,buffer,strlen(buffer));close(socketfd);return 0;} 

上面程序中，server.c和client.c中的缓存区故意设置不一样大，为了检验从服务器读取数据是否正常。使用如下方式来编译和运行程序

$gcc -o server server.c

$gcc -o client client.c

$./server

另起一个终端

$./client "hello server, this a test!"

可见，上面发送的一句话大小超过了10字节，但是小于30-1字节，如果大于30-1字节将出现问题，缓存区溢出了。由于有一个结束符'/0'，所以只能是30-9个字符。