ack/lang/m2/libm2/Traps.mod
1988-02-19 15:54:01 +00:00

90 lines
1.8 KiB
Modula-2

(*
(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: $Header$
*)
IMPORT EM;
IMPORT Unix;
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 EM.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, q: POINTER TO CHAR;
l: CARDINAL;
dummy, lino: INTEGER;
buf, buf2: ARRAY [0..255] OF CHAR;
i, j: CARDINAL;
BEGIN
p := EM.FILN();
IF p # NIL THEN
q := p;
WHILE p^ # 0C DO
p := ADDRESS(p) + 1;
END;
dummy := Unix.write(2, q, ADDRESS(p) - ADDRESS(q));
ELSE
l := Argv(0, buf);
dummy := Unix.write(2, ADR(buf), l);
END;
lino := EM.LINO();
i := 0;
IF lino # 0 THEN
i := 2;
buf[0] := ',';
buf[1] := ' ';
IF lino < 0 THEN
buf[2] := '-';
i := 3;
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] := ' ';
dummy := Unix.write(2, ADR(buf), i+2);
i := 0;
WHILE (i <= HIGH(str)) AND (str[i] # 0C) DO
INC(i);
END;
dummy := Unix.write(2, ADR(str), i);
buf[0] := 12C;
dummy := Unix.write(2, ADR(buf), 1);
END Message;
PROCEDURE Trap(n: INTEGER);
(* cause trap number "n" to occur *)
BEGIN
EM.TRP(n);
END Trap;
END Traps.