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#1 2020-03-09 13:19:44
THttpApiWebSocketServer - Free does not return
Hi,
I have a THttpApiWebSocketServer, and when freeing it, at the end of the app, the call will not return. Worked last week Friday (I think) without a problem.
program Project3;
{$APPTYPE CONSOLE}
{$R *.res}
uses
System.SysUtils,
SynCrtSock;
var
WebSocketServer: THttpApiWebSocketServer;
begin
try
WebSocketServer := THttpApiWebSocketServer.Create(False);
WebSocketServer.AddUrlWebSocket('A', '8081', False, '+', True);
Writeln('Freeing');
WebSocketServer.Free;
Writeln('You''ll never see me :-(');
except
on E: Exception do
Writeln(E.ClassName, ': ', E.Message);
end;
Writeln('Done');
Readln;
end.Gets stuck in function TThread.WaitFor: LongWord;
Regards,
Daniel
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#3 2020-03-09 15:50:27
Re: THttpApiWebSocketServer - Free does not return
@sakura - as far as i know ab do not use THttpApiWebSocketServer. I contribute it to mORMot several years ago, but now I also do not use it (migrate all my projects to Linux/FPC). Can you try to debug a problem?
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#4 2020-03-09 19:14:15
Re: THttpApiWebSocketServer - Free does not return
In the end, it stops within the repeat loop:
function TThread.WaitFor: LongWord;
{$IF Defined(MSWINDOWS)}
var
H: array[0..1] of THandle;
WaitResult: Cardinal;
{$IF not Declared(System.Embedded)}
Msg: TMsg;
{$ENDIF}
begin
if FExternalThread then
raise EThread.CreateRes(@SThreadExternalWait);
H[0] := FHandle;
if CurrentThread.ThreadID = MainThreadID then
begin
{$IF not Declared(System.Embedded)}
WaitResult := 0;
{$ENDIF}
H[1] := SyncEvent;
repeat
{$IF Defined(NEXTGEN) and Declared(System.Embedded)}
WaitResult := WaitForMultipleObjects(2, @H, False, 1000);
{$ELSE}
{ This prevents a potential deadlock if the background thread
does a SendMessage to the foreground thread }
if WaitResult = WAIT_OBJECT_0 + 2 then
PeekMessage(Msg, 0, 0, 0, PM_NOREMOVE);
WaitResult := MsgWaitForMultipleObjects(2, H, False, 1000, QS_SENDMESSAGE);
{$ENDIF}
CheckThreadError(WaitResult <> WAIT_FAILED);
if WaitResult = WAIT_OBJECT_0 + 1 then
CheckSynchronize;
until WaitResult = WAIT_OBJECT_0;
end else WaitForSingleObject(H[0], INFINITE);
CheckThreadError(GetExitCodeThread(H[0], Result));
end;MsgWaitForMultipleObjects(2, H, False, 1000, QS_SENDMESSAGE); always returns 258...
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#5 2020-03-11 10:14:04
Re: THttpApiWebSocketServer - Free does not return
What it weird is that it should happen with the previous code too, but less often due to some weird multi-thread magic.
Should be fixed by https://synopse.info/fossil/info/f640a7dc402c311c
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#8 2020-03-11 15:26:50
Re: THttpApiWebSocketServer - Free does not return
Sadly, for me, still, it does not return from the Free call. MsgWaitForMultipleObjects still times out...
P.S.: I've tried it 10 times, only one it returned, all other times, it waited for (whatever)...
Last edited by sakura (2020-03-11 15:28:07)
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#9 2020-03-11 15:33:28
Re: THttpApiWebSocketServer - Free does not return
destructor THttpApiServer.Destroy;
{$ifdef LVCL}
var i: integer;
{$endif}
begin
{$ifdef LVCL}
Terminate; // for Execute to be notified about end of process
{$endif}
try
if (fClones<>nil) and (Http.Module<>0) then // fClones=nil for clone threads
----------- fClones<>nil needed? removing that, it seems to work...
DestroyMainThread;
{$ifdef LVCL}
for i := 1 to 500 do
if fExecuteFinished then
break else
SleepHiRes(10);
{$endif}
finally
inherited Destroy;
end;
end;See comment above. I have not seen - in my demo case - where fClones is accessed within DestroyMainThread, so, it being NIL wouldn't be a problem. But in other cases it might...
Last edited by sakura (2020-03-11 15:33:46)
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#10 2020-03-11 15:49:16
Re: THttpApiWebSocketServer - Free does not return
You are right: the fix was not enough.
Please try https://synopse.info/fossil/info/b2c2d46be6 - which seems fine now in my tests.
The problem was when you had no cloned thread, i.e. ThreadPoolCount=1.
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