getsokname & getpeername

#include
int getsockname(int sockfd,struct sockaddr * localaddr,socklen_t * addrlen);

int getpeername(int connfd,struct sockaddr * peeraddr,socklen_t * addrlen);

两者均返回 : 0--成功 , -1--出错.

注意：
   函数在使用时，第三个参数addrlen要指定地址结构长度。
socklen_t addrlen;
addrlen = sizeof(struct sockaddr_in);

程序代码：

#include
#include
#include
#include
#include
#include
#include

int main()
{
    int sockfd,connfd;
    char buff[100];
    struct sockaddr_in serv,local,cli,peer;
    socklen_t len,addrlen;
    
    sockfd = socket(AF_INET,SOCK_STREAM,0);
    memset(&serv,0,sizeof(serv));
    memset(&local,0,sizeof(local));
    memset(&peer,0,sizeof(peer));
   
    serv.sin_family = AF_INET;
    inet_pton(AF_INET,"127.0.0.1",&serv.sin_addr);
    //serv.sin_addr.s_addr = INADDR_ANY;
    serv.sin_port = htons(5000);
    bind(sockfd,(struct sockaddr *)&serv,sizeof(serv));
    inet_ntop(AF_INET,&serv.sin_addr,buff,sizeof(buff));   
    printf("serv.addr = %s,port=%d \n",buff,ntohs(serv.sin_port));

    memset(&buff,0,sizeof(buff));
   
    len = sizeof(struct sockaddr_in);   
    getsockname(sockfd,(struct sockaddr *)&local,&len);   
    if((inet_ntop(AF_INET,&local.sin_addr,buff,sizeof(buff)))==NULL)
        printf("inet_ntop\n");
    printf("local.addr = %s ,port=%d \n",buff,ntohs(local.sin_port));
    listen(sockfd,14);
    for(;;)
    {
        connfd = accept(sockfd,    (struct sockaddr *)&cli,&addrlen);
        printf("peer connect ...\n");
        memset(buff,0,sizeof(buff));
        if((getpeername(connfd,(struct sockaddr *)&peer,&len))!=0)
            printf("getpeername \n");
        printf("peer.addr = %s, port = %d\n",inet_ntop(AF_INET,&peer.sin_addr,buff,sizeof(buff)),ntohs(peer.sin_port));
    }
    return 0;
}