critical-section

Why is it imposible to enter critical section without Sleep(1)? type TMyThread = class(TThread) public procedure Execute; override; end; var T: TMyThread; c: TRTLCriticalSection; implementation procedure TForm1.FormCreate(Sender: TObject); begin InitializeCriticalSection(c); T := TMyThread.Create(false); end; procedure TMyThread.Execute; begin repeat EnterCriticalSection(c); Sleep(100); LeaveCriticalSection(c); sleep(1); // can't enter from another thread without it until false; end; procedure TForm1.Button1Click(Sender: TObject); begin EnterCriticalSection(c); Caption := 'entered';

Few months back, I had come across this interesting scenario asked by a guy (on orkut). Though, I've come up with a "non-portable" solution to this problem (have tested it with small code), but still would like to know what you guys have to say and suggest. Suppose, I created a DLL, exporting some functionalities, written in C++, for single threaded client . This DLL declares lots of global variables, some maybe const variables (read-only) and others are modifiable. Anyway, later things changed and now I want the same DLL to work with multi-threaded application (without modifying the DLL);

In attempting to create a thread-safe container class from scratch, I've run into the problem of returning values from access methods. For example in Windows: myNode getSomeData( ) { EnterCriticalSection(& myCritSec); myNode retobj; // fill retobj with data from structure LeaveCriticalSection(& myCritSec); return retobj; } Now I suppose that this type of method is not at all thread-safe because after the code releases the critical section another thread is able to come along and immediately overwrite retobj before the first thread returns. So what is an elegant way to return retobj to the

I stucked into a problem with threads syncronization and critical sections on Windows 10. Application will crash in this case: Application has two threads. Thread 1 calls EnterCriticalSection with object m_CS Thread 2 then attempts to enter the same critical section Thread 1 terminates Thread 2 using TerminateThread Thread 1 calls LeaveCriticalSection In previous Windows versions which I was able to test (7, 8, 8.1) this works properly. Thread 2 terminates, and Thread 1 leaves the critical section without exception. On Windows 10, when Thread 1 leaves the critical section, application crashes

Consider the following serial function. When I parallelize my code, every thread will call this function from within the parallel region (not shown). I am trying to make this threadsafe and efficient (fast). float get_stored_value__or__calculate_if_does_not_yet_exist( int A ) { static std::map<int, float> my_map; std::map::iterator it_find = my_map.find(A); //many threads do this often. bool found_A = it_find != my_map.end(); if (found_A) { return it_find->second; } else { float result_for_A = calculate_value(A); //should only be done once, really. my_map[A] = result_for_A; return result_for_A

Is it safe to change VirtualTreeView data from the secondary thread ? And if yes, should I use critical sections (or even Synchronize method) ? I'm afraid that when I'll be writing to the VT's data record from the other thread, main thread invokes its repaint meanwhile and this refresh will cause reading of the same record at one time. I would supplement I'm using only 2 threads in the application. Something like ... type PSomeRecord = ^TSomeRecord; TSomeRecord = record SomeString: string; SomeInteger: integer; SomeBoolean: boolean; end; ... var FCriticalSection: TRTLCriticalSection; // global