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/*
* Copyright (c) 1999-2003 Smithsonian Astrophysical Observatory
*/
#include <unistd.h>
#include <strings.h>
#include <stdio.h>
#include <stdlib.h>
#include <netdb.h> /* gethostbyname() */
#include <arpa/inet.h>
#define SZ_LINE 1024
int main(int argc, char **argv)
{
int i, got;
char host[SZ_LINE];
struct hostent *hostent;
struct addrinfo *hints=NULL, *addrinfo=NULL;
struct sockaddr_in * p;
// gethost
if( argc > 1 )
strcpy(host, argv[1]);
else{
fprintf(stderr, "calling gethostname() ...\n");
if( gethostname(host, SZ_LINE) == -1 ){
perror("gethostname");
exit(1);
}
else{
fprintf(stderr, "host name is %s\n", host);
}
}
fprintf(stderr, "\n");
fprintf(stderr, "calling getaddrinfo (preferred) ...\n");
hints = (struct addrinfo *)calloc(1, sizeof(struct addrinfo));
hints->ai_flags |= AI_CANONNAME;
hints->ai_family = AF_INET;
got = getaddrinfo(host, NULL, hints, &addrinfo);
if( got != 0 ){
fprintf(stderr, "getaddrinfo rtn: %d %s\n", got, gai_strerror(got));
perror("getaddrinfo");
exit(1);
}
else{
fprintf(stderr, "getaddrinfo() succeeded\n");
}
fprintf(stderr, "printing ip address via getaddrinfo ...\n");
if( addrinfo ){
p = (struct sockaddr_in *)(addrinfo->ai_addr);
fprintf(stderr, "%x (canonical: %s)\n", p->sin_addr.s_addr, addrinfo->ai_canonname);
freeaddrinfo(addrinfo);
if( hints ) free(hints);
}
else{
fprintf(stderr, "ERROR: can't look up: %s\n", host);
}
fprintf(stderr, "\n");
fprintf(stderr, "calling gethostbyname (obsolete) ...\n");
if( !(hostent = gethostbyname(host)) ){
perror("gethostbyname");
exit(1);
}
else{
fprintf(stderr, "gethostbyname() succeeded\n");
}
fprintf(stderr, "printing ip address(es) via gethostbyname ...\n");
if( hostent ){
for(i=0; hostent->h_addr_list[i]; i++){
fprintf(stderr, "%x\n", *(int *)hostent->h_addr_list[i]);
}
}
else{
fprintf(stderr, "ERROR: can't look up: %s\n", host);
}
fprintf(stderr, "\n");
return(0);
}
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