I think I've come up with a solution to provide a critical section with a
timeout, and want some feedback, particularly if you can see any problems
with it.
Firstly 2 procedures which are used to enter and leave a section.
var
CS: TRTLCriticalSection;
LockThreadID: Cardinal;
function EnterProc: Boolean;
const
Timeout = 2000; // 2 seconds
var
ThreadID: Cardinal;
Start: Cardinal;
Elapsed: Integer;
OK: Boolean;
begin
EnterCriticalSection(CS);
ThreadID := GetCurrentThreadID;
if ThreadID = LockThreadID then
begin
Result := False;
LeaveCriticalSection(CS);
Exit;
end;
OK := True;
Start := GetTickCount;
while (LockThreadID <> 0) and OK do
begin
Sleep(1);
Elapsed := GetTickCount-Start;
OK := (Elapsed >= 0) and (Elapsed < Timeout);
end;
LockThreadID := ThreadID;
Result := True;
LeaveCriticalSection(CS);
end;
procedure LeaveProc;
begin
LockThreadID := 0;
end;
Note that I don't need speed where these procedures will be used, so the
Sleep(1) delay isn't an issue.
Now to use it.
var Locked: Boolean;
begin
Locked := EnterProc;
try
DoSomething;
finally
If Locked then LeaveProc;
end;
end;
It appears to work.
Ross.
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