// wxConditionInternal
// --------------------------------------------------------------------------
-#if defined(__WXMSW__) || defined(__OS2__) || defined(__EMX__)
// Win32 and OS/2 don't have explicit support for the POSIX condition
// variables and their events/event semaphores have quite different semantics,
// so we reimplement the conditions from scratch using the mutexes and
// semaphores
-#if defined(__OS2__) || defined(__EMX__)
-void InterlockedIncrement(LONG *num)
-{
- ::DosEnterCritSec();
- (*num)++;
- ::DosExitCritSec();
-}
-#endif
+#if defined(__WXMSW__) || defined(__OS2__) || defined(__EMX__)
class wxConditionInternal
{
wxCondError wxConditionInternal::Wait()
{
// increment the number of waiters
- ::InterlockedIncrement(&m_numWaiters);
+ {
+ wxCriticalSectionLocker lock(m_csWaiters);
+ m_numWaiters++;
+ }
m_mutex.Unlock();
// a potential race condition can occur here
//
- // after a thread increments nwaiters, and unlocks the mutex and before the
- // semaphore.Wait() is called, if another thread can cause a signal to be
- // generated
+ // after a thread increments m_numWaiters, and unlocks the mutex and before
+ // the semaphore.Wait() is called, if another thread can cause a signal to
+ // be generated
//
// this race condition is handled by using a semaphore and incrementing the
- // semaphore only if 'nwaiters' is greater that zero since the semaphore,
+ // semaphore only if m_numWaiters is greater that zero since the semaphore,
// can 'remember' signals the race condition will not occur
// wait ( if necessary ) and decrement semaphore
wxCondError wxConditionInternal::WaitTimeout(unsigned long milliseconds)
{
- ::InterlockedIncrement(&m_numWaiters);
+ {
+ wxCriticalSectionLocker lock(m_csWaiters);
+ m_numWaiters++;
+ }
m_mutex.Unlock();
if ( err == wxSEMA_TIMEOUT )
{
// another potential race condition exists here it is caused when a
- // 'waiting' thread timesout, and returns from WaitForSingleObject, but
- // has not yet decremented 'nwaiters'.
+ // 'waiting' thread times out, and returns from WaitForSingleObject,
+ // but has not yet decremented m_numWaiters
//
// at this point if another thread calls signal() then the semaphore
// will be incremented, but the waiting thread will miss it.
//
// to handle this particular case, the waiting thread calls
// WaitForSingleObject again with a timeout of 0, after locking
- // 'nwaiters_mutex'. this call does not block because of the zero
+ // m_csWaiters. This call does not block because of the zero
// timeout, but will allow the waiting thread to catch the missed
// signals.
wxCriticalSectionLocker lock(m_csWaiters);
- err = m_semaphore.WaitTimeout(0);
+ wxSemaError err2 = m_semaphore.WaitTimeout(0);
- if ( err != wxSEMA_NO_ERROR )
+ if ( err2 != wxSEMA_NO_ERROR )
{
m_numWaiters--;
}
return wxCOND_NO_ERROR;
}
-#endif
+
+#endif // MSW or OS2
// ----------------------------------------------------------------------------
// wxCondition