Linux

#include <iostream.h>
#include <netdb.h>
#include <arpa/inet.h>
int main()
{
hostent *host, **host1;
in_addr **addr_ptr;
char hostname[255];
char buff[1024];
int err; 
gethostname(hostname,255);
cout<<"hostname="<<hostname<<"\n";
gethostbyname_r(hostname,host,buff,sizeof(buff),host1,&err);
cout<<"err="<<err<<"\n";
addr_ptr=(struct in_addr**)host->h_addr_list;
char* mgcip=new char[16];
mgcip=inet_ntoa(**addr_ptr);
cout<<"mgcip="<<mgcip<<"\n";
}

$gdb a.out core
GNU gdb 6.0 (MontaVista 6.0-11.0.15.0500398 2005-03-19)
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This GDB was configured as "i686-hardhat-linux"...
Core was generated by `a.out'.
Program terminated with signal 11, Segmentation fault.
Reading symbols from /usr/lib/libstdc++.so.5...done.
Loaded symbols for /usr/lib/libstdc++.so.5
Reading symbols from /lib/libm.so.6...done.
Loaded symbols for /lib/libm.so.6
Reading symbols from /lib/libgcc_s.so.1...done.
Loaded symbols for /lib/libgcc_s.so.1
Reading symbols from /lib/libc.so.6...done.
Loaded symbols for /lib/libc.so.6
Reading symbols from /lib/ld-linux.so.2...done.
Loaded symbols for /lib/ld-linux.so.2
Reading symbols from /lib/libnss_files.so.2...done.
Loaded symbols for /lib/libnss_files.so.2
#0  0x40251345 in internal_getent (result=0x804895c, buffer=0xbfffcb50 "\177", buflen=8192,
    errnop=0x40243be0, herrnop=0xbfffcb4c, af=2, flags=0) at nss_files/files-hosts.c:77
77      nss_files/files-hosts.c: No such file or directory.
        in nss_files/files-hosts.c
(gdb) bt
#0  0x40251345 in internal_getent (result=0x804895c, buffer=0xbfffcb50 "\177", buflen=8192,
    errnop=0x40243be0, herrnop=0xbfffcb4c, af=2, flags=0) at nss_files/files-hosts.c:77
#1  0x402517d5 in _nss_files_gethostbyname_r (name=0xbfffeb50 "oamce-1", result=0x804895c,
    buffer=0xbfffcb50 "\177", buflen=8192, errnop=0x40243be0, herrnop=0xbfffcb4c)
    at nss_files/files-hosts.c:268
#2  0x402066c8 in __gethostbyname_r (name=0xbfffeb50 "oamce-1", resbuf=0x804895c,
    buffer=0xbfffcb50 "\177", buflen=8192, result=0xbfffec58, h_errnop=0xbfffcb4c)
    at getXXbyYY_r.c:219
#3  0x0804882d in main () at 1.cc:13
Current language:  auto; currently c
(gdb)