Sven Barth schrieb:
Am 25.08.2010 16:12, schrieb Alexander Grau:
Sven Barth schrieb:
I looked at your example program and I also looked into FPC's Thread
implementation for Windows. You need to play around with the Heap a
bit more to make things interesting:
Modify someFunc like in the following and someObj.someMethod won't be
executed any more,
Using exactly your modifications, all code ist executed correctly - the
line you indicated is correctly reached and executed. No exceptions
at all.
I'm using FPC 2.4.0 for all my tests - I'm assuming you are using 2.2.4
? (If that is the case there must have been a fix for this to make this
bug gone away).
Yes, I'm using 2.2.4... shame on me for not testing with a current FPC
-.-
Does it even work if you use threadvars? It should as the Heap uses
threadvars, but I want to be sure. (and now I'm also curious to know
why it works with 2.4.0 ^^)
I have modified the test - now it's using multiple external threads and
that works fine too until the moment I enable any 'writeln'. Using
threadvars or not doesn't make any difference. Using any writeln will
make it crash. If not using writeln, the external threads can call FPC
objects to increase some counters that are correctly displayed at the
end of the program for each thread.
program project1;
{$APPTYPE CONSOLE}
{$mode objfpc}{$H+}
uses
{$IFDEF UNIX}{$IFDEF UseCThreads}
cthreads,
{$ENDIF}{$ENDIF}
Classes,
{ you can add units after this }
windows;
{$R project1.res}
type
TSomeClass = class
public
procedure someMethod(idx: integer);
end;
const
COUNT = 30;
var
i: integer;
threadid: DWORD;
ThreadHandles: array[1..COUNT] of THandle; //Rückgabewert von CreateThread
counters: array[1..COUNT] of integer;
someObj: TSomeClass;
procedure TSomeClass.someMethod(idx: integer);
begin
//writeln('TSomeClass.someMethod called');
inc(counters[idx]);
end;
procedure someFunc(param: pointer); cdecl;
var
t: tobject;
begin
//WriteLn('External is called - ThreadID=', GetCurrentThreadId);
//if assigned(param) then writeln('blub');
//writeln('param=', param);
t := TObject.Create;
try
//Writeln(t.ClassName); // <--- here we get a crash
finally
t.Free;
end;
someObj.someMethod(integer(param));
end;
function ExternalThread(param: Pointer): LongInt; stdcall;
begin
someFunc(param);
Result:=0;
end;
begin
WriteLn('Main ThreadID=', GetCurrentThreadId);
someObj:=TSomeClass.create;
for i:=1 to COUNT do counters[i]:=0;
WriteLn('Creating external threads');
for i:=1 to COUNT do
begin
ThreadHandles[i]:=CreateThread(nil, 0,
TFNThreadStartRoutine(@ExternalThread),
pointer(i), 0, ThreadID);
if ThreadHandles[i] = 0 then writeln('ERROR creating external thread');
end;
readln;
WriteLn('Freeing external thread');
for i:=1 to COUNT do
begin
if ThreadHandles[i]<>0 then CloseHandle(ThreadHandles[i]);
end;
someObj.free;
for i:=1 to COUNT do
writeln (counters[i]);
end.
--
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