From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Thu, 19 Feb 1998 23:36:50 +0900
From: Kenji Arisawa arisawa@ar.aichi-u.ac.jp
Subject: [9fans] Alef Guarded Block
Topicbox-Message-UUID: 72548006-eac8-11e9-9e20-41e7f4b1d025
Message-ID: <19980219143650.k6-3J8fJSTuXBNWYO5QACmmTxDgQyMtwKwo_6fcr2a8@z>

Hello 9fans!

Am I misunderstanding the guarded block of Alef?

The program a.l bellow lead to dead lock.
term% 8.out
alice: entering guarded block
alice: waiting msg
carol: entering guarded block
--- dead lock here ! ---

Is this correct result?


----------------------- a.l -------------------------
#include <alef.h>

void alice(chan(int) msg){
        sleep(100);
        print("alice: entering guarded block\n");
        !{
                print("alice: waiting msg\n");
                <- msg;
        }
        print("alice: done\n");
}

void carol(chan(int) msg){
        sleep(130);
        print("carol: entering guarded block\n");
        !{
                print("carol: sending msg\n");
                msg <- = 1;
        }
        print("carol: done\n");
}

void main(void){
        chan(int) msg;
        alloc msg;
        par { alice(msg); carol(msg); }
}
-----------------------------------------------------


Kenji Arisawa
E-mail: arisawa@aichi-u.ac.jp