p12-2.c

SUN Solaris8平台下进程间通信

#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <netdb.h>
#include <stdio.h>
int main(int argc, char *argv[])
{
    char *host, **names, **addrs;
    struct hostent *hostinfo;
    /* 设置主机为命令行参数指定的名字或程序运行所在的机器名字 */
    if(argc == 1) {
        char myname[256];
        gethostname(myname, 255);
        host = myname;
    }
    else
        host = argv[1];
    /* 获取主机地址信息 */
    hostinfo = gethostbyname(host);
    if(!hostinfo) {
        fprintf(stderr, "cannot get info for host: %s\n", host);
        exit(1);
    }
    /* 报告它的正式名和别名 */
    printf("results for host %s:\n", host);
    printf("Official name: %s\n", hostinfo -> h_name);
    printf("\t Aliases:");
    names = hostinfo -> h_aliases;
    while(*names) {
        printf(" %s", *names);
        names++;
    }
    printf("\n");
    /* 如果该主机没有IP地址，警告并退出 */
    if(hostinfo -> h_addrtype != AF_INET) {
        fprintf(stderr, "not an IP host!\n");
        exit(1);
    }
    /* 否则，报告IP地址 */
    addrs = hostinfo -> h_addr_list;
    while(*addrs) {
        printf("\t address: %s", inet_ntoa(*(struct in_addr *)*addrs));
        addrs++;
    }
    printf("\n");
    exit(0);
}