(****************************************************************)
(*                                                              *)
(*         Gardens Point Modula-2 Library Definition            *)
(*                                                              *)
(*                                                              *)
(*     (c) Copyright 1996 Faculty of Information Technology     *)
(*              Queensland University of Technology             *)
(*                                                              *)
(*     Permission is granted to use, copy and change this       *)
(*     program as long as the copyright message is left intact  *)
(*                                                              *)
(****************************************************************)

(* !SYSTEM! *) DEFINITION MODULE ProgArgs;

(* this is a system module; it is known to the compiler and  *)
(* activated by import. There is no explicit implementation. *)

  PROCEDURE ArgNumber() : CARDINAL;
  (* postcondition : returns number of arguments with UNIX   *)
  (*                 conventions. Returns 1 if no args given *)

  PROCEDURE GetArg(num : CARDINAL; VAR arg : ARRAY OF CHAR);
  (* precondition  : 0 <= num <= ArgNumber() - 1             *)
  (* postcondition : arg is a nul terminated string. ( ==>   *)
  (*                 it is fast even if HIGH(arg) >> length) *)

  (* usage example: to simply print all the arguments --

       FOR ix := 0 TO ArgNumber() - 1 DO
         GetArg(ix,str); WriteString(str); WriteLn;
       END;
  *)

  PROCEDURE EnvironString(inStr  : ARRAY OF CHAR;
                      VAR outStr : ARRAY OF CHAR);
  (* precondition  : HIGH(outStr) must be > than length of   *)
  (*                 outString ... no checking is done.      *)
  (* postcondition : outStr holds value of environ variable, *)
  (*                 or an empty string if inStr not defined *)

  PROCEDURE VersionTime(VAR outStr : ARRAY OF CHAR);
  (* precondition  : HIGH(outStr) > 26                       *)
  (* postcondition : outStr is a nul terminated string with  *)
  (*                 the date and time at which the program  *)
  (*                 was built. The string includes newline  *)

  (* usage example: to print version time --
   *
   *   WriteString("Program version of ");
   *   VersionTime(str);
   *   WriteString(str); (* no WriteLn needed *)
   *)

  PROCEDURE UNIXtime() : CARDINAL;
  (* returns time in seconds since 00:00:00, GMT Jan 1 1970 *)

  PROCEDURE UNIXexit(res : CARDINAL);
  (* exits program returning result code res to UNIX caller *)

  PROCEDURE Assert(expr : BOOLEAN;
		   optString : ARRAY OF CHAR);
  (* If expr is FALSE, the program aborts with the message  *)
  (* optString.  The open array is optional, and if used    *)
  (* replaces the module name message which is otherwise    *)
  (* generated                                              *)
  (* From the command line "gpm -a" suppresses assert tests *)

  VAR FP_Overflow : BOOLEAN;
  (*
   * This flag is set by the appropriate signal handler and remains
   * set unless explicitly cleared by the application.
   * The gpm front-end uses it to handle infinity on Alpha's
   * (On most machines the result of an FP overflow is +infinity
   *  On ALPHA it's UNPREDICTABLE.)
   * Typical usage:-
   *		FP_Overflow := FALSE;
   *    	 ... some floating-point calculations
   *		IF (FP_Overflow) THEN
   *		 ... floating-point overflow occurred
   *		END;
   *)
END ProgArgs.
