MODULE CStrProg;
(* C string returns, char ** outputs and C-written CHAR buffers.

   CStr.CString is an explicit ADDRESS alias; CStr.Copy is the
   C-to-Modula-2 conversion.  Expected exit code: 42. *)

FROM CStr IMPORT CString, Length, Copy, IsNil;
FROM CStrTest IMPORT m2_cstr_hello, m2_cstr_out, m2_cstr_fill;

VAR
  ExitCode : INTEGER;
  buf : ARRAY [0..15] OF CHAR;
  p : CString;
  n : CARDINAL;
  ok : BOOLEAN;

BEGIN
  p := m2_cstr_hello();
  ok := (NOT IsNil(p)) AND (Length(p) = 5);
  IF ok THEN
    n := Copy(p, buf);
    ok := (n = 5) AND (buf[0] = 'h') AND (buf[4] = 'o')
          AND (buf[5] = CHR(0))
  END;

  IF ok THEN
    p := NIL;
    ok := IsNil(p) AND (Length(p) = 0);
    IF ok THEN
      m2_cstr_out(p);
      ok := (NOT IsNil(p)) AND (Length(p) = 5);
      IF ok THEN
        n := Copy(p, buf);
        ok := (n = 5) AND (buf[0] = 'w') AND (buf[4] = 'd')
              AND (buf[5] = CHR(0))
      END
    END
  END;

  IF ok THEN
    n := m2_cstr_fill(buf, 16);
    ok := (n = 6) AND (buf[0] = 'b') AND (buf[5] = 'r')
          AND (buf[6] = CHR(0))
  END;

  IF ok THEN
    n := Copy(NIL, buf);
    ok := (n = 0) AND (buf[0] = CHR(0))
  END;

  IF ok THEN ExitCode := 42 ELSE ExitCode := 1 END
END CStrProg.