ubuntu下的c程序，关于无连接套接字通信的，求解！
功能是这样的，客户端给服务端发送消息，客户端把消息再返回给服务端，有两个程序，一个是客户端程序，一个是服务端程序，由于都在同一台机子，
所以服务端程序用的本地ip：127.0.0.1
程序不知道哪里出错了，研究不出来 麻烦前辈帮我看看，绝不是依赖，我真的努力了！感激阿

客户端程序：

C/C++ code

#include<stdio.h>#include<netinet/in.h>#include<arpa/inet.h>#include<unistd.h>#include<fcntl.h>#include<sys/stat.h>#include<sys/types.h>#include<sys/socket.h>#define REMOTEPORT 4567#define REMOTEIP "127.0.0.1"void main(){    int s,len;    struct sockaddr_in addr;    int addr_len;    char msg[256];    int i=0;    if((s=socket(AF_INET,SOCK_DGRAM,0))<0)    {        perror("error");        exit(1);        }    else    {        printf("socket created .\n");        printf("socked id:%d\n",s);        printf("remote ip:%s\n",REMOTEIP);        printf("remote port:%d\n",REMOTEPORT);    }        len=sizeof(struct sockaddr_in);    bzero(&addr,sizeof(addr));    addr.sin_family=AF_INET;    addr.sin_port=htons(REMOTEPORT);    addr.sin_addr.s_addr=inet_addr(REMOTEIP);    while(1)    {        bzero(msg,sizeof(msg));        len=read(STDIN_FILENO,msg,sizeof(msg));        sendto(s,msg,len,0,&addr,&addr_len);        printf("\nInput message: %s",msg);        len=recvfrom(s,msg,sizeof(msg),0,&addr,&addr_len);        printf("%d:",i);        i++;        printf("Received message :%s",msg);    }}

服务端程序：

C/C++ code

#include<stdio.h>#include<netinet/in.h>#include<arpa/inet.h>#include<unistd.h>#include<sys/types.h>#include<sys/socket.h>#define LOCALPORT 4567void main(){    int mysock,len;    struct sockaddr_in addr;    int i=0;    char msg[256];    int addr_len;        if((mysock=socket(AF_INET,SOCK_DGRAM,0))<0)    {        perror("error");        exit(1);    }    else    {        printf("socket created .\n");        printf("socked id :%d\n",mysock);    }    addr_len=sizeof(struct sockaddr_in);    bzero(&addr,sizeof(addr));    addr.sin_family=AF_INET;    addr.sin_port=htons(LOCALPORT);    addr.sin_addr.s_addr=htonl(INADDR_ANY);    if(bind(mysock,&addr,sizeof(addr))<0)    {        perror("connect");        exit(1);    }    else    {        printf("bind ok.\n");        printf("local port :%d\n",LOCALPORT);    }    while(1)    {        bzero(msg,sizeof(msg));        len=recvfrom(mysock,msg,sizeof(msg),0,&addr,&addr_len);        printf("%d: ",i++);        printf("message from :%s\n",inet_ntoa(addr.sin_addr));        printf("message length : %d\n",len);        printf("message:%s\n\n",msg);        sendto(mysock,msg,len,0,&addr,addr_len);    }}

[解决办法]
len=read(STDIN_FILENO,msg,sizeof(msg));
sendto(s,msg,len,0,&addr,&addr_len);

addr_len 没有赋值过。
[解决办法]
客户端len=sizeof(struct sockaddr_in);

改成

addr_len = sizeof(struct sockaddr_in);

或者

addr_len = sizeof(addr);

[解决办法]
一楼回答有问题，UDP是不用accept的

3L正解，没测... 应该没问题吧