On Mon, 27 Nov 2006 00:14:39 +0100, Matthew Comb <[EMAIL PROTECTED]>
wrote:
You are creating your critical section within your worker thread. This
won't protect anything as all of your worker threads will have their own
instance of the critical section.
Hmm, I do this at a few more places too. What should I do instead?
Actually, THIS may be what's causing the error. When I process a keyword,
I put the result into the following structure:
GoogleResult = ^ResultRec;
ResultRec = packed record
next: GoogleResult;
srNo: integer;
// etc...
end;
This GoogleResult is then used as a global variable. The main form has a
public property
ResultList: GoogleResult. Each thread has a pointer back to the main form.
To ass the result to the list, I write
AddItem(mainForm.ResultList, newItem);
And this is the procedure:
procedure AddItem(var list: GoogleResult; const item: GoogleResult);
var
tmp: GoogleResult;
critical: _RTL_CRITICAL_SECTION;
begin
try
InitializeCriticalSection(critical);
EnterCriticalSection(critical);
if list = nil then
list := item
else begin
tmp := list;
while tmp^.next <> nil do
tmp := tmp^.next;
tmp^.next := item;
end;
LeaveCriticalSection(critical);
DeleteCriticalSection(critical);
except on Exception do { nothing }
end
end;
You see I've put everything in a critical section? So this won't do
anything because I'm calling the procedure from the thread? What should I
do instead, use Synchronize?
Hmm or maybe I should just use a TThreadList here as well. I've left this
old list for historical reasons (in the previous version the program was
single threaded).
You are creating your critical section to access a boolean ? This is not
needed as you cannot have a conflict on a boolean type.
There's a checkbox on the main form which enables/disables caching. If I
change it while a thread is accessing the variable then there can be a
conflict.
Are any of your worker threads passed the same file name ? This for sure
would cause a problem.
No they each create their own random-named file, before making sure it
doesn't exist.
Csaba
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