Error Given by Compiler

QNX DEVELOPERS General Programming
1

Hi,

I tried to compile the following source code on QNX 6.3.0.
I am trying to use the C function to create socket.

/******************* Start Of Code ***************************/
#include <stdio.h>

#include <sys/types.h>

#include <sys/socket.h>
#include <netinet/in.h>

#include <errno.h>
#include <net/if.h>
#include <ioctl.h>

int GetInterfaceAddress (const char *, unsigned long int *);

int main ()
{
unsigned long int addr;

if (GetInterfaceAddress(“lo0”, &addr) == -1)
printf("%s: %s: ‘%s’\n", “GetInterfaceAddress”, “failed”, “lo0”);
else
printf("%s addr %d.%d.%d.%d\n", “lo0”, (int)*(unsigned char )&addr,
(int)((unsigned char )&addr + 1), (int)((unsigned char )&addr + 2),
(int)((unsigned char *)&addr + 3));

if (GetInterfaceAddress(“en1”, &addr) == -1)
printf("%s: %s: ‘%s’\n", “GetInterfaceAddress”, “failed”, “en1”);
else
printf("%s addr %d.%d.%d.%d\n", “en1”, (int)*(unsigned char )&addr,
(int)((unsigned char )&addr + 1), (int)((unsigned char )&addr + 2),
(int)((unsigned char *)&addr + 3));

if (GetInterfaceAddress(“en2”, &addr) == -1)
printf("%s: %s: ‘%s’\n", “GetInterfaceAddress”, “failed”, “en2”);
else
printf("%s addr %d.%d.%d.%d\n", “en2”, (int)*(unsigned char )&addr,
(int)((unsigned char )&addr + 1), (int)((unsigned char )&addr + 2),
(int)((unsigned char *)&addr + 3));

return 0;
}

int GetInterfaceAddress (const char *if_name, unsigned long int *addr)
{
struct ifreq ifr;
int s;

if (!if_name)
{
*addr = INADDR_ANY;
return 0;
}

if ((s = socket(AF_INET, SOCK_STREAM, 0)) == -1)
{
//printf("%s: %s\n", “socket()”, strerror(errno));
return -1;
}

strcpy(ifr.ifr_name, if_name);

if (ioctl(s, SIOCGIFADDR, &ifr) == -1)
{
printf("%s: %s\n", “ioctl()”, strerror(errno));
return -1;
}

if (close(s) == -1)
return -1;

*addr = ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr.s_addr;

return 0;
}

/********************* End of Code **************************** /

The compiler produce an error as follow:

  • In function GetInterfaceAddress': undefined reference to socket’

I checked the header file, socket.h. The function socket() is included in the header file.

what could have gone wrong?
Is there any settting I have to make to the setting of compiler so that the source code above can be compiled successfully?

Can anybody help me on this?

Rgds

2

The error doesn’t come from the compiler but from the linker. You need to link with the socket library by specify -lsocket