inet_ntoa 的一个小问题

浏览数：28 / 时间：2015年06月09日

一个简单点的阻塞式tcp服务器如下所示：

#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
                                                                                                                  
 
int main(int 
argc, char**argv)
{
    int 
listenfd,connfd,n, ret;
    struct 
sockaddr_in servaddr, cliaddr;
    socklen_t clilen;
    pid_t     childpid;
    char 
mesg[1000], *peeraddr;
 
    listenfd = socket(AF_INET, SOCK_STREAM, 0);
    if 
(listenfd < 0) {
        printf("create socket error\n");
        return 
-1;
    }
    printf("create socket success\n");
 
    memset(&servaddr, 0, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(6789);
 
    ret = bind(listenfd, (struct 
sockaddr *)&servaddr, sizeof(servaddr));
    if 
(ret == -1) {
        printf("bind error\n");
        return 
-1;
    }
    printf("bind success\n");
 
    ret = listen(listenfd, 1024);
    if 
(ret == -1) {
        printf("listen error\n");
        return 
-1;
    }
 
    printf("listening...\n");
 
    for 
(;;) {
        clilen = sizeof(cliaddr);
        connfd = accept(listenfd, (struct 
sockaddr *)&cliaddr, &clilen);
 
        printf("Accept request from %s\n", inet_ntoa(cliaddr.sin_addr));
 
        n = read(connfd, mesg, 1000);
        if 
(n < 0) {
            printf("read error!\n");
        }
 
        printf("Received:%s\n", mesg);
 
        close(connfd);
    }
}

　　编译期间没有遇到问题。运行的时候程序在47行收到了segment fault错误。用man手册查看inet_ntoa，调用方式如下：

1	`char` `*inet_ntoa(struct` `in_addr in);`

　　cliaddr的类型定义是：

struct sockaddr_in { /* in netinet/in.h */

<em id="__mceDel">       sa_family_t       sin_family;
       in_port_t         sin_port;
       struct 
in_addr    sin_addr;   
       unsigned char     
sin_zero[sizeof(struct 
sockaddr) - sizeof(sa_family_t) - sizeof(in_port_t), sizeof(struct 
in_addr)];
};
</em>