(*
* Producer/Consumer Test Module
*
* This module tests the WAIT and SEND functions
* found in the Processes module and is adapted
* from code found on page 346 of Advanced Modula-2
* by Herber Schildt available from McGraw-Hill.
*
*)
MODULE ProCon;
FROM Terminal IMPORT WriteLn,WriteString;
FROM SYSTEM IMPORT WORD,PROCESS,ADR,NEWPROCESS,TRANSFER;
FROM Processes IMPORT WAIT,SEND,StartProcess,Init,SIGNAL;
VAR
buf: ARRAY[0..100] OF CHAR;
S: SIGNAL;
PROCEDURE Consumer;
BEGIN
LOOP
WriteString("waiting"); (* This portion of the loop is *)
WriteLn; (* executed only once !!! *)
WAIT(S); (* Wait for characters from buffer *)
WriteLn; (* Subsequent SEND's cause looping on the *)
WriteString(buf); (* WAIT rather than going to the statement *)
END; (* after the LOOP? is it a bug or the way its *)
END Consumer; (* supposed to work? *)
PROCEDURE Producer;
VAR
count: CARDINAL;
ch: CHAR;
BEGIN
count := 0;
LOOP
READ(ch); (* Clear character buffer *)
IF (ch <> CHR(13)) AND (count < 99) THEN
buf[count] := ch;
WRITE(ch);
INC(count);
ELSE
buf[count] := CHR(0); (* Null terminator *)
count := 0;
SEND(S);
END;
END;
END Producer;
BEGIN
Init(S);
StartProcess(Consumer,1000);
Producer;
