"warning: assignment makes integer from pointer without a cast" in C

[christyyim]

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

warning: assignment makes integer from pointer without a cast

Here is my 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.

[coopstah13]

i'm not a C programmer, but it seems to me that you are trying to assign a char pointer to a boolean with b = pch, when pch is a character pointer and b is a boolean

[christyyim]

thanks coopstah13. The reason i did so is because the pch i get in the end will be either yes or no and since i had defined yes and no to 1 and 0 respectively before the main program, that is why i assigned it to a boolean with b=pch.

Even though i also agree with you that the warning is most probably because of this assignment, but I have no idea on how to solve it as I'm a beginner to C programming.

[GNU-Fan]

thanks coopstah13. The reason i did so is because the pch i get in the end will be either yes or no

Who said that?
strtok will return a pointer to char. Therefore, pch will be of the value NULL or non NULL. Finding Tokens in a String - The GNU C Library

So if you want b to be 1 in case pch is non-null, you need something like

b = (pch != NULL);

[christyyim]

yah, GNU-Fan, you hit the nail on the head!!! Thanks

I misunderstood the way how strtok works. And now i use strstr function instead of strtok. Thanks.