[Lazarus] Mutlithreaded Dll Callback crashes my Application

[José Mejuto]

Hello Lazarus-List,

Wednesday, August 25, 2010, 8:44:53 AM, you wrote:

MW> I've packed the runtime env dlls and put them on my ftp server.
MW> They are too big to attach to the mail on the list.

Do you have compiled the "vcmtdll.dll" with Multithread runtime
library (/MT) ?

To avoid crashes just simply:

// start threads
for index := 0 to FThreads.Count-1 do
begin
   TVCMTThread(FThreads.Items[index]).Start(10);
   Sleep(50);
end;

Adding the Sleep(50) avoids any crash, and the AsyncWrite works as
expected. You should also add a Sleep(50) after each FThreads[n].free

If a multithread problem is solved with sleeps usually it is a race
condition in the RTL, in this case you create a new thread while the
provious one is being created (or destroyed), so to me looks like a
VC++ non multithread RTL problem.

It is also desirable to add the line "IsMultithread:=true" in the
first line of .lpr (after the begin) to activate the Multithread RTL
in the FPC, otherwise it could not be active.

I had tested it with 200 threads and using the sleeps no problem at
all.

-- 
Best regards,
 José