Listing 1

       /* 1*/ #include <stdio.h>  /* MS-DOS-specific */
       
       /* 3*/ main()
       /* 4*/ {
       /* 5*/      FILE *fp;
       /* 6*/      char filename[] = "\test.dat";
       
       /* 8*/      fp = fopen(filename, "r");
       /* 9*/      if (fp == NULL)
       /*10*/          printf ("Can't open file %s\n", filename);
       /*11*/      else {
       /*12*/          printf("File open\n");
       /*13*/          fclose(fp);
       /*14*/      }
       /*15*/ }

Output:
       
       Can't open file est.dat