warning: assignment makes integer from pointer without a cast

Here is the code I wrote to detect whether a LAN cable is pluged or unpluged. After compilation, it gives me the warning:

Code:

warning: assignment makes integer from pointer without a cast

Here is my code:

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define yes 1
#define no 0
typedef int boolean; 

int main()
{
  FILE *fp;
  char *pch;
  char line[130];			/* line of easa!from unix command*/
  int m;
  boolean b;
   
  fp = popen("nm-tool | grep Link", "r");		/* Issue the command.		*/

					/* Read a line			*/
  while ( fgets( line, sizeof line, fp))
  {
    printf("%s", line);
  }
  pclose(fp);

  pch = strtok (line," 	");
  for (m=0; m<2; m++)
  {
    pch = strtok (NULL, " 	");
  }
    printf ("%s\n",pch);
  b = pch;
  printf("%d\n",b);		/* more to add on */

  return 0;
}

I have googled some solutions online, like include the stdlib.h header and etc but all didn't work. Does anyone has any idea on it?

Thanks in advance.

Change:

Code:

b = pch;

to:

Code:

b = pch != NULL;