(*  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.  See the copyright notice in the ACK home directory, in the file "Copyright".*)(*$R-*)IMPLEMENTATION MODULE Traps;(*  Module:       Facility for handling traps  Author:       Ceriel J.H. Jacobs  Version:      $Header: /cvsup/minix/src/lib/ack/libm2/Traps.mod,v 1.1 2005/10/10 15:27:46 beng Exp $*)  FROM	EM IMPORT	SIG, LINO, FILN, TRP;  FROM	Unix IMPORT	write;  FROM	SYSTEM IMPORT	ADDRESS, ADR;  FROM	Arguments IMPORT			Argv;  PROCEDURE InstallTrapHandler(t: TrapHandler): TrapHandler;  (* Install a new trap handler, and return the previous one.     Parameter of trap handler is the trap number.  *)  BEGIN	RETURN SIG(t);  END InstallTrapHandler;  PROCEDURE Message(str: ARRAY OF CHAR);  (* Write message "str" on standard error, preceeded by filename and     linenumber if possible  *)  VAR 	p: POINTER TO CHAR;	l: CARDINAL;	lino: INTEGER;	buf, buf2: ARRAY [0..255] OF CHAR;	i, j: CARDINAL;  BEGIN	p := FILN();	IF p # NIL THEN		i := 1;		buf[0] := '"';		WHILE p^ # 0C DO			buf[i] := p^;			INC(i);			p := ADDRESS(p) + 1;		END;		buf[i] := '"';		INC(i);		IF write(2, ADR(buf), i) < 0 THEN END;	ELSE		l := Argv(0, buf);		IF write(2, ADR(buf), l-1) < 0 THEN END;	END;	lino := LINO();	i := 0;	IF lino # 0 THEN		i := 7;		buf[0] := ','; buf[1] := ' ';		buf[2] := 'l'; buf[3] := 'i'; buf[4] := 'n'; buf[5] := 'e';		buf[6] := ' ';		IF lino < 0 THEN			buf[7] := '-';			i := 8;			lino := - lino;		END;		j := 0;		REPEAT			buf2[j] := CHR(CARDINAL(lino) MOD 10 + ORD('0'));			lino := lino DIV 10;			INC(j);		UNTIL lino = 0;		WHILE j > 0 DO			DEC(j);			buf[i] := buf2[j];			INC(i);		END;	END;	buf[i] := ':';	buf[i+1] := ' ';	IF write(2, ADR(buf), i+2) < 0 THEN END;	i := 0;	WHILE (i <= HIGH(str)) AND (str[i] # 0C) DO		INC(i);	END;	IF write(2, ADR(str), i) < 0 THEN END;	buf[0] := 12C;	IF write(2, ADR(buf), 1) < 0 THEN END;  END Message;  PROCEDURE Trap(n: INTEGER);  (* cause trap number "n" to occur *)  BEGIN	TRP(n);  END Trap;END Traps.