/* We can't simply return c - '0' because this is ANSI  */
  /* C code, so it has to work for any character set, not */
  /* just ones which put the digits together in order.    */

/* Puts the decimal value of the string s into *pn, returning */
/* 1 on success. If s is empty, or contains non-digits,       */
/* or represents an integer greater than 9999, then *pn       */
/* is not changed and 0 is returned. Does not use errmsg.     */

/* Reads lines from stdin until EOF, or until a blank line is encountered, */
/* in which case the newline is pushed back onto the input stream. Returns */
/* a NULL-terminated array of pointers to individual lines, stripped of    */
/* their newline characters. Uses errmsg, and returns NULL on failure.     */