<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">I don't know that there ever was a mandate that join can only be called once on a given thread. But, given that pthread_join is undefined when called more than once on the same thread we probably want to retain the comment. (Whether the implementation actually prohibits it or not is an implementation decision.) The point is that we should be free to give the error in some later implementation, so as to not to restrict what semantics the implementation must support.<div><br><div> <span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; color: rgb(0, 0, 0); font-family: Helvetica; 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font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; -webkit-text-decorations-in-effect: none; text-indent: 0px; -webkit-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><div><font class="Apple-style-span" color="#0000FF"><font class="Apple-style-span" face="Gill Sans"><span class="Apple-style-span" style="color: rgb(0, 0, 255); font-family: 'Gill Sans'; "><span class="Apple-style-span" style="color: rgb(0, 0, 255); font-family: 'Gill Sans'; ">Antony Hosking</span></span></font></font><font class="Apple-style-span" face="Gill Sans"><span class="Apple-style-span" style="font-family: 'Gill Sans'; "><span class="Apple-style-span" style="font-family: 'Gill Sans'; "><span class="Apple-converted-space"> </span>|<span class="Apple-converted-space"> </span></span></span><span class="Apple-style-span" style="font-family: 'Gill Sans'; "><span class="Apple-style-span" style="font-family: 'Gill Sans'; ">Associate Professor</span></span><span class="Apple-style-span" style="font-family: 'Gill Sans'; "><span class="Apple-style-span" style="font-family: 'Gill Sans'; "> | Computer Science | Purdue University</span></span></font></div><div><font class="Apple-style-span" face="GillSans-Light"><span class="Apple-style-span" style="font-family: GillSans-Light; ">305 N. University Street | West Lafayette | IN 47907 | USA</span></font></div><div><font class="Apple-style-span" color="#0000FF" face="Gill Sans"><span class="Apple-style-span" style="color: rgb(0, 0, 255); font-family: 'Gill Sans'; "><span class="Apple-style-span" style="color: rgb(0, 0, 255); font-family: 'Gill Sans'; ">Office</span></span></font><font class="Apple-style-span" face="GillSans-Light"><span class="Apple-style-span" style="font-family: GillSans-Light; "><span class="Apple-style-span" style="font-family: GillSans-Light; "> +1 765 494 6001 |<span class="Apple-converted-space"> </span></span></span></font><font class="Apple-style-span" color="#0000FF" face="Gill Sans"><span class="Apple-style-span" style="color: rgb(0, 0, 255); font-family: 'Gill Sans'; "><span class="Apple-style-span" style="color: rgb(0, 0, 255); font-family: 'Gill Sans'; ">Mobile</span></span></font><font class="Apple-style-span" face="GillSans-Light"><span class="Apple-style-span" style="font-family: GillSans-Light; "><span class="Apple-style-span" style="font-family: GillSans-Light; "><span class="Apple-converted-space"> </span>+1 765 427 5484</span></span></font></div><div><font class="Apple-style-span" face="GillSans-Light"><br class="khtml-block-placeholder"></font></div></span></span></span></span></span></span></span><br class="Apple-interchange-newline"></span></div></span></div></span><br class="Apple-interchange-newline"> </div><br><div><div>On 2 Nov 2009, at 10:11, Jay K wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div class="hmmessage" style="font-size: 10pt; font-family: Verdana; ">Thread.i3:<br> <br> <br>PROCEDURE Join(t: T): REFANY;<br>(* Wait until "t" has terminated and return its result. It is a<br> checked runtime error to call this more than once for any "t". *)<br><br> <br>ThreadWin32.m3:<br> <br> <br>PROCEDURE Join(t: T): REFANY =<br> VAR res: REFANY;<br> BEGIN<br> LOCK t DO<br> IF t.joined THEN Die(ThisLine(), "attempt to join with thread twice"); END;<br> WHILE NOT t.completed DO Wait(t, t.join) END;<br> res := t.result;<br> t.result := NIL;<br> t.joined := TRUE;<br> t.join := NIL;<br> END;<br> RETURN res;<br> END Join;<br> <br>PROCEDURE AlertJoin(t: T): REFANY RAISES {Alerted} = similar<br><br><br>ThreadPThread.m3:<br> <br><br>PROCEDURE Join (t: T): REFANY =<br> BEGIN<br> LOCK t DO<br> WHILE NOT t.completed DO Wait(t, t.join) END;<br> END;<br> RETURN t.result;<br> END Join;<br> <br>PROCEDURE AlertJoin (t: T): REFANY RAISES {Alerted} = similar<br><br> <br>Should we just loosen the comment and go with the simpler pthread version?<br>I'd like Win32 and pthread to be more similar where possible, to ease maintenance.<br> <br> <br> - Jay<br></div></span></blockquote></div><br></div></body></html>