APUE第16章的示例运行16-8

来源：互联网发布：淘宝版本低不能买东西编辑：程序博客网时间：2024/06/05 04:21

博客声明：http://blog.csdn.net/up_seeker/article/details/8887257

最近在学习APUE第十六章的时候老是在运行的关口卡住，现将自己或别人的解决办法拿出来共享，有更好办法的希望拿出来和大家晒晒………

APUE的16-8.c是将命令行给出的主机名和服务中的信息通过getaddrinfo映射到IP地址和端口，并打印出一些主机名、协议类型、端口信息等

代码：

#include "apue.h" //注意，这个头文件是APUE前面讲到的一些常用的函数，在此没有给出，所以不能直接运行！#include <netdb.h>#include <arpa/inet.h>#if defined(BSD) || defined(MACOS)#include <sys/socket.h>#include <netinet/in.h>#endifvoid print_family(struct addrinfo *aip){printf(" family: ");switch(aip->ai_family) {case AF_INET: printf("inet"); break;case AF_INET6:printf("inet6");break;case AF_UNIX: printf("unix"); break;case AF_UNSPEC:printf("unspecified");break;default: printf("unknown");}return;}void print_type(struct addrinfo *aip){printf(" type: ");switch(aip->ai_socktype) {case SOCK_STREAM: printf("stream"); break;case SOCK_DGRAM:  printf("datagram");break;case SOCK_SEQPACKET: printf("seqpacket");break;case SOCK_RAW: printf("ram"); break;default: printf("unknown(%d)\n", aip->ai_socktype);}return;}void print_protocol(struct addrinfo *aip){printf(" protocol: ");switch(aip->ai_protocol) {case 0:printf("default"); break;case IPPROTO_TCP: printf("tcp"); break;case IPPROTO_UDP: printf("udp"); break;case IPPROTO_RAW: printf("raw"); break;default: printf("unknow(%d)", aip->ai_protocol);}return;}void print_flags(struct addrinfo *aip){printf(" flag: ");if (aip->ai_flags == 0) {printf(" 0");} else {if (aip->ai_flags & AI_PASSIVE)printf(" passive ");if (aip->ai_flags & AI_CANONNAME)printf(" canonname ");if (aip->ai_flags & AI_NUMERICHOST)printf(" numerichost ");#if defined(AI_NUMERICSERV)if (aip->ai_flags & AI_NUMERICSERV)printf(" numricserv ");#endif#if defined(AI_V4MAPPED)if (aip->ai_flags & AI_V4MAPPED)printf(" v4mapped ");#endif#if defined(AI_ALL)if (aip->ai_flags & AI_ALL)printf(" all ");#endif}return;}//if you want test this program, please type "./a.out IP_addr service_name", for example, ./a.out 192.168.1.1 nfsint main(int argc, char *argv[]){struct addrinfo *aip, *ailist;struct addrinfo hint;struct sockaddr_in *sinp;const char *addr;interr;char abuf[INET_ADDRSTRLEN];if (argc != 3) err_quit("Usage:%s nodename service.", argv[0]);hint.ai_flags = AI_CANONNAME;hint.ai_family = 0;hint.ai_socktype = 0;hint.ai_protocol = 0;hint.ai_addrlen = 0;hint.ai_canonname = NULL;hint.ai_addr = NULL;hint.ai_next = NULL;if ((err = getaddrinfo(argv[1], argv[2], &hint, &ailist)) != 0) //你传入的参数都派上了用场err_quit("getaddrinfo error:%s", gai_strerror(err));for (aip = ailist; aip != NULL; aip = aip->ai_next) {print_flags(aip);print_family(aip);print_type(aip);print_protocol(aip);printf("\n\thost: %s ", aip->ai_canonname ? aip->ai_canonname : "-");if (aip->ai_family == AF_INET) {sinp = (struct sockaddr_in *)aip->ai_addr;addr = inet_ntop(AF_INET, &sinp->sin_addr, abuf, INET_ADDRSTRLEN);printf(" address: %s ", addr ? addr:"unknown");printf(" port: %d", ntohs(sinp->sin_port));}printf("\n");}exit(0);}

APUE上给出的运行方式为：./a.out harry nfs

在运行时如果完全按照APUE上的可能得不到结果，因为你要确保你的linux/Unix上有harry这个用户/主机,，其实就是给出相应的地址，所以我在运行时捣鼓了半天准备放弃，最后灵光了一下，用如下办法得出结果：./a.out 127.0.0.1 nfs

注：127.0.0.1是回环测试地址

另外，你可以通过查看/etc/hosts中的内容，会看到有IP和名字对应的信息(我的前两行分别是localhost和Uuntu及其对应的IP)，你可以用里面有的IP或名字来使用，包括APUE的16章后面的内容都能用到，去看一下吧！

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