Listing 4

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

  main()
  {
    char *pc;

    if (putenv("test=1234") == -1)
       printf("cannot define string\n");
    else {
       printf("string definition added\n");
       pc = getenv("test");
       printf("string defined as >%s<\n", pc);
       system("see");
    }
  }



                 Output

  string definition added
  string defined as >1234<