Code for finding enviroment variable location

gistfile1.txt

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

int main(int argc, char *argv[]) {
   char *ptr;

   if(argc < 3) {
      printf("Usage: %s <envvar> <program>\n", argv[0]);
      exit(0);
   }
   ptr = getenv(argv[1]); /* Get env var location. */
   ptr += (strlen(argv[0]) - strlen(argv[2]))*2; /* Adjust for program name. */
   printf("%p\n", ptr);
}