Function            isdir - is a FAT entry a subdirectory

  Syntax              boolean isdir(char *fspec);

  Prototype in        filehk.h

  Remarks             checks if a FAT entry is a valid subdirectory. The
                      string fspec should be in the following format:

                           [d:][path]filename.ext[\]

                      where

                           d: = optional drive letter
                           path = optional path
                           filename.ext = the name of the FAT entry you
                                          want to check
                      fspec may optionally have a \ at the end

                      Wildcards (*,?) are NOT supported and always cause
                      isdir to return FALSE.

                      This function does not harm the dta. The dta is
                      modified by this function, but restored before
                      returning.

  Return value        returns TRUE if fspec is a subdirectory, FALSE if
                      fspec does not exist or is not a subdirectory.

  See also            fileexist()

  Example             #include <filehk.h>

                      main()
                      {
                           char dirname[] = "a:\util\";

                           printf("%s is ",dirname);
                           if (! isdir())
                                printf("not ");
                           printf("a subdirectory\n");
                      }