MODULE multi;
(* multi-language demonstration program *)
(* demonstrates how to call C from Modula and vice versa *)

(* There are 3 modules, implemented by the following source files              *)
(* multi.mod                         : main module)                            *)
(* multi1.c,   multi1.def            : module written in C, called from Modula *)
(* multi2.mod, multi2.def, multi2.h  : module written in Modula, called from C *)

FROM math IMPORT atan2;
FROM stdlib IMPORT system;
FROM stdio IMPORT printf;
IMPORT IO;
IMPORT multi1;

CONST NL = CHAR(10);
CONST pi = 3.141592654;
VAR x,y:LONGREAL;
BEGIN
  IO.WrStr("IO.WrStr called from Modula" );
  IO.WrLn;

  multi1.x(1,2,3,4);
  multi1.y(1,2,3,4);

  system('dir multi*.*'); (* C system function (quite convenient) *)

  x := 1.2;
  y := 1.2;
  printf( "atan2(%f,%f) = %f, pi/4=%f" + NL, x, y, atan2(x,y), LONGREAL(pi/4.0) );

  (* Note that you cannot use "\n" in string constants because this
     is a compile-time notation of the C language, instead use
     string concatenation of NL *)

  (* Also note that REAL arguments for printf have to be converted to LONGREAL,
    since this is what printf expects *)

END multi.