Hello, how do I convert from IP address to network byte order and then back to IP address using char and long?
I have:
char ipaddress[15]='127.0.0.1';
long x;
x=inet_addr(ipaddress);
printf("x=%d\n",x);
but how do I do the reverse if I know x equals some value and want to convert back to a character array with the dotted decimal IP?
Thanks!
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Hi,
Tried that, when I compiled I got
error: incompatible type for argument 1 of 'inet_ntoa'
Any thoughts? Here is the remainder of the code:
int main(int nArg, char* pszArgs[])
{
char ipaddr[15]="127.0.0.1";
long x;
char ipaddrx[15];
x=inet_addr(ipaddr);
printf("inet_addr(%s)=%l\n
char* ipaddry=inet_ntoa(x);
printf("inet_ntoa(x)=%s\n"
return 0;
}
Thanks!
Hi Amit G
Still getting errors. Here is where I am:
{
char ipaddr[15]="127.0.0.1";
unsigned long x;
char ipaddrx[15];
x=inet_addr(ipaddr);
printf("inet_addr(%s)=%l\n
struct in_addr x_r;
x_r.S_un.S_addr=x;
char* ipaddry=inet_ntoa(x);
printf("inet_ntoa(x)=%s\n"
return 0;
}
And the error:
htonl.c:26: error: 'struct in_addr' has no member named 'S_un'
htonl.c:27: error: incompatible type for argument 1 of 'inet_ntoa'
Also tried with lower-case 's' on x_r.s_un.s_addr and same error.
Any other thoughts?
Thanks
Hi Amit G
htonl.c:26: error: 'struct in_addr' has no member named 'S_un'
Changing x to x_r took care of the first one.
I'm using a Mac, include files are below (this is just one piece of a much larger program).
#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
#include <pthread.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <netdb.h>
Thanks!
Getting warmer :) Now it compiles but I get a bus error:
#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
#include <pthread.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <netdb.h>
int main(int nArg, char* pszArgs[])
{
char ipaddr[15]="127.0.0.1";
unsigned long x;
char ipaddrx[15];
x=inet_addr(ipaddr);
printf("inet_addr(%s)=%d\n
struct in_addr x_r;
x_r.s_addr=x;
char* ipaddry=inet_ntoa(x_r);
printf("inet_ntoa(x_r)=%s\
return 0;
}
inet_addr(127.0.0.1)=16777
Bus error
(ran it on a FC6 box and it produced a segmentation fault)
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by: amit_gPosted on 2007-07-24 at 17:17:17ID: 19561262
char* ipaddress_r = inet_ntoa(x);