#pragma implementation "thread.h"
#endif
-// With simple makefiles, we must ignore the file body if not using
-// threads.
-#include "wx/setup.h"
+#include "wx/defs.h"
#if wxUSE_THREADS
#include <sched.h>
#endif
+#ifdef HAVE_THR_SETCONCURRENCY
+ #include <thread.h>
+#endif
+
+// we use wxFFile under Linux in GetCPUCount()
+#ifdef __LINUX__
+ #include "wx/ffile.h"
+#endif
+
// ----------------------------------------------------------------------------
// constants
// ----------------------------------------------------------------------------
STATE_EXITED // thread doesn't exist any more
};
+// the exit value of a thread which has been cancelled
+static const wxThread::ExitCode EXITCODE_CANCELLED = (wxThread::ExitCode)-1;
+
+// our trace mask
+#define TRACE_THREADS _T("thread")
+
+// ----------------------------------------------------------------------------
+// private functions
+// ----------------------------------------------------------------------------
+
+static void ScheduleThreadForDeletion();
+static void DeleteThread(wxThread *This);
+
+// ----------------------------------------------------------------------------
+// private classes
+// ----------------------------------------------------------------------------
+
+// same as wxMutexLocker but for "native" mutex
+class MutexLock
+{
+public:
+ MutexLock(pthread_mutex_t& mutex)
+ {
+ m_mutex = &mutex;
+ if ( pthread_mutex_lock(m_mutex) != 0 )
+ {
+ wxLogDebug(_T("pthread_mutex_lock() failed"));
+ }
+ }
+
+ ~MutexLock()
+ {
+ if ( pthread_mutex_unlock(m_mutex) != 0 )
+ {
+ wxLogDebug(_T("pthread_mutex_unlock() failed"));
+ }
+ }
+
+private:
+ pthread_mutex_t *m_mutex;
+};
+
// ----------------------------------------------------------------------------
// types
// ----------------------------------------------------------------------------
// the key for the pointer to the associated wxThread object
static pthread_key_t gs_keySelf;
-// this mutex must be acquired before any call to a GUI function
-static wxMutex *gs_mutexGui;
+// the number of threads which are being deleted - the program won't exit
+// until there are any left
+static size_t gs_nThreadsBeingDeleted = 0;
+
+// a mutex to protect gs_nThreadsBeingDeleted
+static pthread_mutex_t gs_mutexDeleteThread;
+
+// and a condition variable which will be signaled when all
+// gs_nThreadsBeingDeleted will have been deleted
+static wxCondition *gs_condAllDeleted = (wxCondition *)NULL;
+
+#if wxUSE_GUI
+ // this mutex must be acquired before any call to a GUI function
+ static wxMutex *gs_mutexGui;
+#endif // wxUSE_GUI
// ============================================================================
// implementation
class wxMutexInternal
{
public:
- pthread_mutex_t p_mutex;
+ pthread_mutex_t m_mutex;
};
wxMutex::wxMutex()
{
- p_internal = new wxMutexInternal;
-
- pthread_mutex_init( &(p_internal->p_mutex), (const pthread_mutexattr_t*) NULL );
+ m_internal = new wxMutexInternal;
+
+ pthread_mutex_init(&(m_internal->m_mutex),
+ (pthread_mutexattr_t*) NULL );
m_locked = 0;
}
wxMutex::~wxMutex()
{
if (m_locked > 0)
- wxLogDebug(T("Freeing a locked mutex (%d locks)"), m_locked);
+ wxLogDebug(wxT("Freeing a locked mutex (%d locks)"), m_locked);
- pthread_mutex_destroy( &(p_internal->p_mutex) );
- delete p_internal;
+ pthread_mutex_destroy( &(m_internal->m_mutex) );
+ delete m_internal;
}
wxMutexError wxMutex::Lock()
{
- int err = pthread_mutex_lock( &(p_internal->p_mutex) );
+ int err = pthread_mutex_lock( &(m_internal->m_mutex) );
if (err == EDEADLK)
{
- wxLogDebug(T("Locking this mutex would lead to deadlock!"));
+ wxLogDebug(wxT("Locking this mutex would lead to deadlock!"));
return wxMUTEX_DEAD_LOCK;
}
return wxMUTEX_BUSY;
}
- int err = pthread_mutex_trylock( &(p_internal->p_mutex) );
+ int err = pthread_mutex_trylock( &(m_internal->m_mutex) );
switch (err)
{
case EBUSY: return wxMUTEX_BUSY;
}
else
{
- wxLogDebug(T("Unlocking not locked mutex."));
+ wxLogDebug(wxT("Unlocking not locked mutex."));
return wxMUTEX_UNLOCKED;
}
- pthread_mutex_unlock( &(p_internal->p_mutex) );
+ pthread_mutex_unlock( &(m_internal->m_mutex) );
return wxMUTEX_NO_ERROR;
}
// wxCondition (Posix implementation)
//--------------------------------------------------------------------
+// The native POSIX condition variables are dumb: if the condition is signaled
+// before another thread starts to wait on it, the signal is lost and so this
+// other thread will be never woken up. It's much more convenient to us to
+// remember that the condition was signaled and to return from Wait()
+// immediately in this case (this is more like Win32 automatic event objects)
+
class wxConditionInternal
{
public:
- pthread_cond_t p_condition;
+ wxConditionInternal();
+ ~wxConditionInternal();
+
+ void Wait();
+ bool WaitWithTimeout(const timespec* ts);
+
+ void Signal();
+ void Broadcast();
+
+ void WaitDone();
+ bool ShouldWait();
+ bool HasWaiters();
+
+private:
+ bool m_wasSignaled; // TRUE if condition was signaled while
+ // nobody waited for it
+ size_t m_nWaiters; // TRUE if someone already waits for us
+
+ pthread_mutex_t m_mutexProtect; // protects access to vars above
+
+ pthread_mutex_t m_mutex; // the mutex used with the condition
+ pthread_cond_t m_condition; // the condition itself
};
+wxConditionInternal::wxConditionInternal()
+{
+ m_wasSignaled = FALSE;
+ m_nWaiters = 0;
+
+ if ( pthread_cond_init(&m_condition, (pthread_condattr_t *)NULL) != 0 )
+ {
+ // this is supposed to never happen
+ wxFAIL_MSG( _T("pthread_cond_init() failed") );
+ }
+
+ if ( pthread_mutex_init(&m_mutex, (pthread_mutexattr_t *)NULL) != 0 ||
+ pthread_mutex_init(&m_mutexProtect, NULL) != 0 )
+ {
+ // neither this
+ wxFAIL_MSG( _T("wxCondition: pthread_mutex_init() failed") );
+ }
+
+ // initially the mutex is locked, so no thread can Signal() or Broadcast()
+ // until another thread starts to Wait()
+ if ( pthread_mutex_lock(&m_mutex) != 0 )
+ {
+ wxFAIL_MSG( _T("wxCondition: pthread_mutex_lock() failed") );
+ }
+}
+
+wxConditionInternal::~wxConditionInternal()
+{
+ if ( pthread_cond_destroy( &m_condition ) != 0 )
+ {
+ wxLogDebug(_T("Failed to destroy condition variable (some "
+ "threads are probably still waiting on it?)"));
+ }
+
+ if ( pthread_mutex_unlock( &m_mutex ) != 0 )
+ {
+ wxLogDebug(_T("wxCondition: failed to unlock the mutex"));
+ }
+
+ if ( pthread_mutex_destroy( &m_mutex ) != 0 ||
+ pthread_mutex_destroy( &m_mutexProtect ) != 0 )
+ {
+ wxLogDebug(_T("Failed to destroy mutex (it is probably locked)"));
+ }
+}
+
+void wxConditionInternal::WaitDone()
+{
+ MutexLock lock(m_mutexProtect);
+
+ m_wasSignaled = FALSE;
+ m_nWaiters--;
+}
+
+bool wxConditionInternal::ShouldWait()
+{
+ MutexLock lock(m_mutexProtect);
+
+ if ( m_wasSignaled )
+ {
+ // the condition was signaled before we started to wait, reset the
+ // flag and return
+ m_wasSignaled = FALSE;
+
+ return FALSE;
+ }
+
+ // we start to wait for it
+ m_nWaiters++;
+
+ return TRUE;
+}
+
+bool wxConditionInternal::HasWaiters()
+{
+ MutexLock lock(m_mutexProtect);
+
+ if ( m_nWaiters )
+ {
+ // someone waits for us, signal the condition normally
+ return TRUE;
+ }
+
+ // nobody waits for us and may be never will - so just remember that the
+ // condition was signaled and don't do anything else
+ m_wasSignaled = TRUE;
+
+ return FALSE;
+}
+
+void wxConditionInternal::Wait()
+{
+ if ( ShouldWait() )
+ {
+ if ( pthread_cond_wait( &m_condition, &m_mutex ) != 0 )
+ {
+ // not supposed to ever happen
+ wxFAIL_MSG( _T("pthread_cond_wait() failed") );
+ }
+ }
+
+ WaitDone();
+}
+
+bool wxConditionInternal::WaitWithTimeout(const timespec* ts)
+{
+ bool ok;
+
+ if ( ShouldWait() )
+ {
+ switch ( pthread_cond_timedwait( &m_condition, &m_mutex, ts ) )
+ {
+ case 0:
+ // condition signaled
+ ok = TRUE;
+ break;
+
+ default:
+ wxLogDebug(_T("pthread_cond_timedwait() failed"));
+
+ // fall through
+
+ case ETIMEDOUT:
+ case EINTR:
+ // wait interrupted or timeout elapsed
+ ok = FALSE;
+ }
+ }
+ else
+ {
+ // the condition had already been signaled before
+ ok = TRUE;
+ }
+
+ WaitDone();
+
+ return ok;
+}
+
+void wxConditionInternal::Signal()
+{
+ if ( HasWaiters() )
+ {
+ MutexLock lock(m_mutex);
+
+ if ( pthread_cond_signal( &m_condition ) != 0 )
+ {
+ // shouldn't ever happen
+ wxFAIL_MSG(_T("pthread_cond_signal() failed"));
+ }
+ }
+}
+
+void wxConditionInternal::Broadcast()
+{
+ if ( HasWaiters() )
+ {
+ MutexLock lock(m_mutex);
+
+ if ( pthread_cond_broadcast( &m_condition ) != 0 )
+ {
+ // shouldn't ever happen
+ wxFAIL_MSG(_T("pthread_cond_broadcast() failed"));
+ }
+ }
+}
+
wxCondition::wxCondition()
{
- p_internal = new wxConditionInternal;
- pthread_cond_init( &(p_internal->p_condition), (const pthread_condattr_t *) NULL );
+ m_internal = new wxConditionInternal;
}
wxCondition::~wxCondition()
{
- pthread_cond_destroy( &(p_internal->p_condition) );
-
- delete p_internal;
+ delete m_internal;
}
-void wxCondition::Wait(wxMutex& mutex)
+void wxCondition::Wait()
{
- pthread_cond_wait( &(p_internal->p_condition), &(mutex.p_internal->p_mutex) );
+ m_internal->Wait();
}
-bool wxCondition::Wait(wxMutex& mutex, unsigned long sec, unsigned long nsec)
+bool wxCondition::Wait(unsigned long sec, unsigned long nsec)
{
- struct timespec tspec;
+ timespec tspec;
- tspec.tv_sec = time(0L)+sec;
+ tspec.tv_sec = time(0L) + sec; // FIXME is time(0) correct here?
tspec.tv_nsec = nsec;
- return (pthread_cond_timedwait(&(p_internal->p_condition), &(mutex.p_internal->p_mutex), &tspec) != ETIMEDOUT);
+
+ return m_internal->WaitWithTimeout(&tspec);
}
void wxCondition::Signal()
{
- pthread_cond_signal( &(p_internal->p_condition) );
+ m_internal->Signal();
}
void wxCondition::Broadcast()
{
- pthread_cond_broadcast( &(p_internal->p_condition) );
+ m_internal->Broadcast();
}
//--------------------------------------------------------------------
void Wait();
// wake up threads waiting for our termination
void SignalExit();
+ // wake up threads waiting for our start
+ void SignalRun() { m_condRun.Signal(); }
// go to sleep until Resume() is called
void Pause();
// resume the thread
// "cancelled" flag
void SetCancelFlag() { m_cancelled = TRUE; }
bool WasCancelled() const { return m_cancelled; }
+ // exit code
+ void SetExitCode(wxThread::ExitCode exitcode) { m_exitcode = exitcode; }
+ wxThread::ExitCode GetExitCode() const { return m_exitcode; }
+
+ // the pause flag
+ void SetReallyPaused(bool paused) { m_isPaused = paused; }
+ bool IsReallyPaused() const { return m_isPaused; }
+
+ // tell the thread that it is a detached one
+ void Detach()
+ {
+ m_shouldBeJoined = m_shouldBroadcast = FALSE;
+ m_isDetached = TRUE;
+ }
+ // but even detached threads need to notifyus about their termination
+ // sometimes - tell the thread that it should do it
+ void Notify() { m_shouldBroadcast = TRUE; }
private:
pthread_t m_threadId; // id of the thread
wxThreadState m_state; // see wxThreadState enum
int m_prio; // in wxWindows units: from 0 to 100
- // set when the thread should terminate
+ // this flag is set when the thread should terminate
bool m_cancelled;
- // this (mutex, cond) pair is used to synchronize the main thread and this
- // thread in several situations:
- // 1. The thread function blocks until condition is signaled by Run() when
- // it's initially created - this allows thread creation in "suspended"
- // state
- // 2. The Delete() function blocks until the condition is signaled when the
- // thread exits.
- // GL: On Linux, this may fail because we can have a deadlock in either
- // SignalExit() or Wait(): so we add m_end_mutex for the finalization.
- wxMutex m_mutex, m_end_mutex;
- wxCondition m_cond;
-
- // another (mutex, cond) pair for Pause()/Resume() usage
- //
- // VZ: it's possible that we might reuse the mutex and condition from above
- // for this too, but as I'm not at all sure that it won't create subtle
- // problems with race conditions between, say, Pause() and Delete() I
- // prefer this may be a bit less efficient but much safer solution
- wxMutex m_mutexSuspend;
+ // this flag is set when the thread is blocking on m_condSuspend
+ bool m_isPaused;
+
+ // the thread exit code - only used for joinable (!detached) threads and
+ // is only valid after the thread termination
+ wxThread::ExitCode m_exitcode;
+
+ // many threads may call Wait(), but only one of them should call
+ // pthread_join(), so we have to keep track of this
+ wxCriticalSection m_csJoinFlag;
+ bool m_shouldBeJoined;
+ bool m_shouldBroadcast;
+ bool m_isDetached;
+
+ // VZ: it's possible that we might do with less than three different
+ // condition objects - for example, m_condRun and m_condEnd a priori
+ // won't be used in the same time. But for now I prefer this may be a
+ // bit less efficient but safer solution of having distinct condition
+ // variables for each purpose.
+
+ // this condition is signaled by Run() and the threads Entry() is not
+ // called before it is done
+ wxCondition m_condRun;
+
+ // this one is signaled when the thread should resume after having been
+ // Pause()d
wxCondition m_condSuspend;
+
+ // finally this one is signalled when the thread exits
+ wxCondition m_condEnd;
};
+// ----------------------------------------------------------------------------
+// thread startup and exit functions
+// ----------------------------------------------------------------------------
+
void *wxThreadInternal::PthreadStart(void *ptr)
{
wxThread *thread = (wxThread *)ptr;
- wxThreadInternal *pthread = thread->p_internal;
- void *status;
+ wxThreadInternal *pthread = thread->m_internal;
+ // associate the thread pointer with the newly created thread so that
+ // wxThread::This() will work
int rc = pthread_setspecific(gs_keySelf, thread);
if ( rc != 0 )
{
return (void *)-1;
}
+
+ // have to declare this before pthread_cleanup_push() which defines a
+ // block!
+ bool dontRunAtAll;
+
#if HAVE_THREAD_CLEANUP_FUNCTIONS
- // Install the cleanup handler.
+ // install the cleanup handler which will be called if the thread is
+ // cancelled
pthread_cleanup_push(wxThreadInternal::PthreadCleanup, ptr);
-#endif
+#endif // HAVE_THREAD_CLEANUP_FUNCTIONS
// wait for the condition to be signaled from Run()
- // mutex state: currently locked by the thread which created us
- pthread->m_cond.Wait(pthread->m_mutex);
- // mutex state: locked again on exit of Wait()
+ pthread->m_condRun.Wait();
- // call the main entry
- status = thread->Entry();
+ // test whether we should run the run at all - may be it was deleted
+ // before it started to Run()?
+ {
+ wxCriticalSectionLocker lock(thread->m_critsect);
+ dontRunAtAll = pthread->GetState() == STATE_NEW &&
+ pthread->WasCancelled();
+ }
+
+ if ( !dontRunAtAll )
+ {
+ // call the main entry
+ pthread->m_exitcode = thread->Entry();
+
+ wxLogTrace(TRACE_THREADS, _T("Thread %ld left its Entry()."),
+ pthread->GetId());
+
+ {
+ wxCriticalSectionLocker lock(thread->m_critsect);
+
+ wxLogTrace(TRACE_THREADS, _T("Thread %ld changes state to EXITED."),
+ pthread->GetId());
+
+ // change the state of the thread to "exited" so that
+ // PthreadCleanup handler won't do anything from now (if it's
+ // called before we do pthread_cleanup_pop below)
+ pthread->SetState(STATE_EXITED);
+ }
+ }
+
+ // NB: at least under Linux, pthread_cleanup_push/pop are macros and pop
+ // contains the matching '}' for the '{' in push, so they must be used
+ // in the same block!
#if HAVE_THREAD_CLEANUP_FUNCTIONS
+ // remove the cleanup handler without executing it
pthread_cleanup_pop(FALSE);
-#endif
+#endif // HAVE_THREAD_CLEANUP_FUNCTIONS
- // terminate the thread
- thread->Exit(status);
+ if ( dontRunAtAll )
+ {
+ delete thread;
- wxFAIL_MSG(T("wxThread::Exit() can't return."));
+ return EXITCODE_CANCELLED;
+ }
+ else
+ {
+ // terminate the thread
+ thread->Exit(pthread->m_exitcode);
+
+ wxFAIL_MSG(wxT("wxThread::Exit() can't return."));
- return NULL;
+ return NULL;
+ }
}
#if HAVE_THREAD_CLEANUP_FUNCTIONS
-// Only called when the thread is explicitely killed.
+// this handler is called when the thread is cancelled
void wxThreadInternal::PthreadCleanup(void *ptr)
{
wxThread *thread = (wxThread *) ptr;
- // The thread is already considered as finished.
- if (thread->p_internal->GetState() == STATE_EXITED)
- return;
+ {
+ wxCriticalSectionLocker lock(thread->m_critsect);
+ if ( thread->m_internal->GetState() == STATE_EXITED )
+ {
+ // thread is already considered as finished.
+ return;
+ }
+ }
- // first call user-level clean up code
- thread->OnExit();
+ // exit the thread gracefully
+ thread->Exit(EXITCODE_CANCELLED);
+}
- // next wake up the threads waiting for us (OTOH, this function won't retur
- // until someone waited for us!)
- thread->p_internal->SetState(STATE_EXITED);
+#endif // HAVE_THREAD_CLEANUP_FUNCTIONS
- thread->p_internal->SignalExit();
-}
-#endif
+// ----------------------------------------------------------------------------
+// wxThreadInternal
+// ----------------------------------------------------------------------------
wxThreadInternal::wxThreadInternal()
{
m_state = STATE_NEW;
m_cancelled = FALSE;
+ m_prio = WXTHREAD_DEFAULT_PRIORITY;
+ m_threadId = 0;
+ m_exitcode = 0;
- // this mutex is locked during almost all thread lifetime - it will only be
- // unlocked in the very end
- m_mutex.Lock();
-
- // this mutex is used by wxThreadInternal::Wait() and by
- // wxThreadInternal::SignalExit(). We don't use m_mutex because of a
- // possible deadlock in either Wait() or SignalExit().
- m_end_mutex.Lock();
+ // set to TRUE only when the thread starts waiting on m_condSuspend
+ m_isPaused = FALSE;
- // this mutex is used in Pause()/Resume() and is also locked all the time
- // unless the thread is paused
- m_mutexSuspend.Lock();
+ // defaults for joinable threads
+ m_shouldBeJoined = TRUE;
+ m_shouldBroadcast = TRUE;
+ m_isDetached = FALSE;
}
wxThreadInternal::~wxThreadInternal()
{
- // GL: moved to SignalExit
- // m_mutexSuspend.Unlock();
-
- // note that m_mutex will be unlocked by the thread which waits for our
- // termination
-
- // In the case, we didn't start the thread, all these mutex are locked:
- // we must unlock them.
- if (m_mutex.IsLocked())
- m_mutex.Unlock();
-
- if (m_end_mutex.IsLocked())
- m_end_mutex.Unlock();
-
- if (m_mutexSuspend.IsLocked())
- m_mutexSuspend.Unlock();
}
wxThreadError wxThreadInternal::Run()
{
wxCHECK_MSG( GetState() == STATE_NEW, wxTHREAD_RUNNING,
- T("thread may only be started once after successful Create()") );
+ wxT("thread may only be started once after Create()") );
- // the mutex was locked on Create(), so we will be able to lock it again
- // only when the thread really starts executing and enters the wait -
- // otherwise we might signal the condition before anybody is waiting for it
- wxMutexLocker lock(m_mutex);
- m_cond.Signal();
+ SignalRun();
- m_state = STATE_RUNNING;
+ SetState(STATE_RUNNING);
return wxTHREAD_NO_ERROR;
-
- // now the mutex is unlocked back - but just to allow Wait() function to
- // terminate by relocking it, so the net result is that the worker thread
- // starts executing and the mutex is still locked
}
void wxThreadInternal::Wait()
{
- wxCHECK_RET( WasCancelled(), T("thread should have been cancelled first") );
-
// if the thread we're waiting for is waiting for the GUI mutex, we will
// deadlock so make sure we release it temporarily
if ( wxThread::IsMain() )
wxMutexGuiLeave();
- // entering Wait() releases the mutex thus allowing SignalExit() to acquire
- // it and to signal us its termination
- m_cond.Wait(m_end_mutex);
+ bool isDetached = m_isDetached;
+ long id = (long)GetId();
+ wxLogTrace(TRACE_THREADS, _T("Starting to wait for thread %ld to exit."),
+ id);
+
+ // wait until the thread terminates (we're blocking in _another_ thread,
+ // of course)
+ m_condEnd.Wait();
+
+ wxLogTrace(TRACE_THREADS, _T("Finished waiting for thread %ld."), id);
- // mutex is still in the locked state - relocked on exit from Wait(), so
- // unlock it - we don't need it any more, the thread has already terminated
- m_end_mutex.Unlock();
+ // we can't use any member variables any more if the thread is detached
+ // because it could be already deleted
+ if ( !isDetached )
+ {
+ // to avoid memory leaks we should call pthread_join(), but it must
+ // only be done once
+ wxCriticalSectionLocker lock(m_csJoinFlag);
+
+ if ( m_shouldBeJoined )
+ {
+ // FIXME shouldn't we set cancellation type to DISABLED here? If
+ // we're cancelled inside pthread_join(), things will almost
+ // certainly break - but if we disable the cancellation, we
+ // might deadlock
+ if ( pthread_join((pthread_t)id, &m_exitcode) != 0 )
+ {
+ wxLogError(_("Failed to join a thread, potential memory leak "
+ "detected - please restart the program"));
+ }
- // After that, we wait for the real end of the other thread.
- pthread_join(GetId(), NULL);
+ m_shouldBeJoined = FALSE;
+ }
+ }
// reacquire GUI mutex
if ( wxThread::IsMain() )
void wxThreadInternal::SignalExit()
{
- // GL: Unlock mutexSuspend here.
- m_mutexSuspend.Unlock();
+ wxLogTrace(TRACE_THREADS, _T("Thread %ld about to exit."), GetId());
- // as mutex is currently locked, this will block until some other thread
- // (normally the same which created this one) unlocks it by entering Wait()
- m_end_mutex.Lock();
+ SetState(STATE_EXITED);
- // wake up all the threads waiting for our termination
- m_cond.Broadcast();
+ // wake up all the threads waiting for our termination - if there are any
+ if ( m_shouldBroadcast )
+ {
+ wxLogTrace(TRACE_THREADS, _T("Thread %ld signals end condition."),
+ GetId());
- // after this call mutex will be finally unlocked
- m_end_mutex.Unlock();
+ m_condEnd.Broadcast();
+ }
}
void wxThreadInternal::Pause()
// the state is set from the thread which pauses us first, this function
// is called later so the state should have been already set
wxCHECK_RET( m_state == STATE_PAUSED,
- T("thread must first be paused with wxThread::Pause().") );
+ wxT("thread must first be paused with wxThread::Pause().") );
- // don't pause the thread which is being terminated - this would lead to
- // deadlock if the thread is paused after Delete() had called Resume() but
- // before it had time to call Wait()
- if ( WasCancelled() )
- return;
+ wxLogTrace(TRACE_THREADS, _T("Thread %ld goes to sleep."), GetId());
// wait until the condition is signaled from Resume()
- m_condSuspend.Wait(m_mutexSuspend);
+ m_condSuspend.Wait();
}
void wxThreadInternal::Resume()
{
wxCHECK_RET( m_state == STATE_PAUSED,
- T("can't resume thread which is not suspended.") );
+ wxT("can't resume thread which is not suspended.") );
- // we will be able to lock this mutex only when Pause() starts waiting
- wxMutexLocker lock(m_mutexSuspend);
- m_condSuspend.Signal();
+ // the thread might be not actually paused yet - if there were no call to
+ // TestDestroy() since the last call to Pause() for example
+ if ( IsReallyPaused() )
+ {
+ wxLogTrace(TRACE_THREADS, _T("Waking up thread %ld"), GetId());
+
+ // wake up Pause()
+ m_condSuspend.Signal();
+
+ // reset the flag
+ SetReallyPaused(FALSE);
+ }
+ else
+ {
+ wxLogTrace(TRACE_THREADS, _T("Thread %ld is not yet really paused"),
+ GetId());
+ }
SetState(STATE_RUNNING);
}
// -----------------------------------------------------------------------------
-// static functions
+// wxThread static functions
// -----------------------------------------------------------------------------
wxThread *wxThread::This()
void wxThread::Yield()
{
+#ifdef HAVE_SCHED_YIELD
sched_yield();
+#endif
}
void wxThread::Sleep(unsigned long milliseconds)
wxUsleep(milliseconds);
}
+int wxThread::GetCPUCount()
+{
+#if defined(__LINUX__)
+ // read from proc (can't use wxTextFile here because it's a special file:
+ // it has 0 size but still can be read from)
+ wxLogNull nolog;
+
+ wxFFile file(_T("/proc/cpuinfo"));
+ if ( file.IsOpened() )
+ {
+ // slurp the whole file
+ wxString s;
+ if ( file.ReadAll(&s) )
+ {
+ // (ab)use Replace() to find the number of "processor" strings
+ size_t count = s.Replace(_T("processor"), _T(""));
+ if ( count > 0 )
+ {
+ return count;
+ }
+
+ wxLogDebug(_T("failed to parse /proc/cpuinfo"));
+ }
+ else
+ {
+ wxLogDebug(_T("failed to read /proc/cpuinfo"));
+ }
+ }
+#elif defined(_SC_NPROCESSORS_ONLN)
+ // this works for Solaris
+ int rc = sysconf(_SC_NPROCESSORS_ONLN);
+ if ( rc != -1 )
+ {
+ return rc;
+ }
+#endif // different ways to get number of CPUs
+
+ // unknown
+ return -1;
+}
+
+bool wxThread::SetConcurrency(size_t level)
+{
+#ifdef HAVE_THR_SETCONCURRENCY
+ int rc = thr_setconcurrency(level);
+ if ( rc != 0 )
+ {
+ wxLogSysError(rc, _T("thr_setconcurrency() failed"));
+ }
+
+ return rc == 0;
+#else // !HAVE_THR_SETCONCURRENCY
+ // ok only for the default value
+ return level == 0;
+#endif // HAVE_THR_SETCONCURRENCY/!HAVE_THR_SETCONCURRENCY
+}
+
// -----------------------------------------------------------------------------
// creating thread
// -----------------------------------------------------------------------------
-wxThread::wxThread()
+wxThread::wxThread(wxThreadKind kind)
{
// add this thread to the global list of all threads
gs_allThreads.Add(this);
- p_internal = new wxThreadInternal();
+ m_internal = new wxThreadInternal();
+
+ m_isDetached = kind == wxTHREAD_DETACHED;
}
wxThreadError wxThread::Create()
{
- if (p_internal->GetState() != STATE_NEW)
+ if ( m_internal->GetState() != STATE_NEW )
+ {
+ // don't recreate thread
return wxTHREAD_RUNNING;
+ }
// set up the thread attribute: right now, we only set thread priority
pthread_attr_t attr;
pthread_attr_init(&attr);
#ifdef HAVE_THREAD_PRIORITY_FUNCTIONS
- int prio;
- if ( pthread_attr_getschedpolicy(&attr, &prio) != 0 )
+ int policy;
+ if ( pthread_attr_getschedpolicy(&attr, &policy) != 0 )
{
wxLogError(_("Cannot retrieve thread scheduling policy."));
}
- int min_prio = sched_get_priority_min(prio),
- max_prio = sched_get_priority_max(prio);
+#ifdef __VMS__
+ /* the pthread.h contains too many spaces. This is a work-around */
+# undef sched_get_priority_max
+#undef sched_get_priority_min
+#define sched_get_priority_max(_pol_) \
+ (_pol_ == SCHED_OTHER ? PRI_FG_MAX_NP : PRI_FIFO_MAX)
+#define sched_get_priority_min(_pol_) \
+ (_pol_ == SCHED_OTHER ? PRI_FG_MIN_NP : PRI_FIFO_MIN)
+#endif
+
+ int max_prio = sched_get_priority_max(policy),
+ min_prio = sched_get_priority_min(policy),
+ prio = m_internal->GetPriority();
if ( min_prio == -1 || max_prio == -1 )
{
wxLogError(_("Cannot get priority range for scheduling policy %d."),
- prio);
+ policy);
+ }
+ else if ( max_prio == min_prio )
+ {
+ if ( prio != WXTHREAD_DEFAULT_PRIORITY )
+ {
+ // notify the programmer that this doesn't work here
+ wxLogWarning(_("Thread priority setting is ignored."));
+ }
+ //else: we have default priority, so don't complain
+
+ // anyhow, don't do anything because priority is just ignored
}
else
{
struct sched_param sp;
- pthread_attr_getschedparam(&attr, &sp);
- sp.sched_priority = min_prio +
- (p_internal->GetPriority()*(max_prio-min_prio))/100;
- pthread_attr_setschedparam(&attr, &sp);
+ if ( pthread_attr_getschedparam(&attr, &sp) != 0 )
+ {
+ wxFAIL_MSG(_T("pthread_attr_getschedparam() failed"));
+ }
+
+ sp.sched_priority = min_prio + (prio*(max_prio - min_prio))/100;
+
+ if ( pthread_attr_setschedparam(&attr, &sp) != 0 )
+ {
+ wxFAIL_MSG(_T("pthread_attr_setschedparam(priority) failed"));
+ }
}
#endif // HAVE_THREAD_PRIORITY_FUNCTIONS
#ifdef HAVE_PTHREAD_ATTR_SETSCOPE
// this will make the threads created by this process really concurrent
- pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM);
+ if ( pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM) != 0 )
+ {
+ wxFAIL_MSG(_T("pthread_attr_setscope(PTHREAD_SCOPE_SYSTEM) failed"));
+ }
#endif // HAVE_PTHREAD_ATTR_SETSCOPE
+ // VZ: assume that this one is always available (it's rather fundamental),
+ // if this function is ever missing we should try to use
+ // pthread_detach() instead (after thread creation)
+ if ( m_isDetached )
+ {
+ if ( pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED) != 0 )
+ {
+ wxFAIL_MSG(_T("pthread_attr_setdetachstate(DETACHED) failed"));
+ }
+
+ // never try to join detached threads
+ m_internal->Detach();
+ }
+ //else: threads are created joinable by default, it's ok
+
// create the new OS thread object
- int rc = pthread_create(p_internal->GetIdPtr(), &attr,
- wxThreadInternal::PthreadStart, (void *)this);
- pthread_attr_destroy(&attr);
+ int rc = pthread_create
+ (
+ m_internal->GetIdPtr(),
+ &attr,
+ wxThreadInternal::PthreadStart,
+ (void *)this
+ );
+
+ if ( pthread_attr_destroy(&attr) != 0 )
+ {
+ wxFAIL_MSG(_T("pthread_attr_destroy() failed"));
+ }
if ( rc != 0 )
{
- p_internal->SetState(STATE_EXITED);
+ m_internal->SetState(STATE_EXITED);
+
return wxTHREAD_NO_RESOURCE;
}
wxThreadError wxThread::Run()
{
- return p_internal->Run();
+ wxCriticalSectionLocker lock(m_critsect);
+
+ wxCHECK_MSG( m_internal->GetId(), wxTHREAD_MISC_ERROR,
+ wxT("must call wxThread::Create() first") );
+
+ return m_internal->Run();
}
// -----------------------------------------------------------------------------
{
wxCHECK_RET( ((int)WXTHREAD_MIN_PRIORITY <= (int)prio) &&
((int)prio <= (int)WXTHREAD_MAX_PRIORITY),
- T("invalid thread priority") );
+ wxT("invalid thread priority") );
wxCriticalSectionLocker lock(m_critsect);
- switch ( p_internal->GetState() )
+ switch ( m_internal->GetState() )
{
case STATE_NEW:
// thread not yet started, priority will be set when it is
- p_internal->SetPriority(prio);
+ m_internal->SetPriority(prio);
break;
case STATE_RUNNING:
struct sched_param sparam;
sparam.sched_priority = prio;
- if ( pthread_setschedparam(p_internal->GetId(),
+ if ( pthread_setschedparam(m_internal->GetId(),
SCHED_OTHER, &sparam) != 0 )
{
wxLogError(_("Failed to set thread priority %d."), prio);
case STATE_EXITED:
default:
- wxFAIL_MSG(T("impossible to set thread priority in this state"));
+ wxFAIL_MSG(wxT("impossible to set thread priority in this state"));
}
}
{
wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect);
- return p_internal->GetPriority();
+ return m_internal->GetPriority();
}
-unsigned long wxThread::GetID() const
+unsigned long wxThread::GetId() const
{
- return (unsigned long)p_internal->GetId();
+ return (unsigned long)m_internal->GetId();
}
// -----------------------------------------------------------------------------
wxThreadError wxThread::Pause()
{
+ wxCHECK_MSG( This() != this, wxTHREAD_MISC_ERROR,
+ _T("a thread can't pause itself") );
+
wxCriticalSectionLocker lock(m_critsect);
- if ( p_internal->GetState() != STATE_RUNNING )
+ if ( m_internal->GetState() != STATE_RUNNING )
{
- wxLogDebug(T("Can't pause thread which is not running."));
+ wxLogDebug(wxT("Can't pause thread which is not running."));
return wxTHREAD_NOT_RUNNING;
}
- p_internal->SetState(STATE_PAUSED);
+ wxLogTrace(TRACE_THREADS, _T("Asking thread %ld to pause."),
+ GetId());
+
+ // just set a flag, the thread will be really paused only during the next
+ // call to TestDestroy()
+ m_internal->SetState(STATE_PAUSED);
return wxTHREAD_NO_ERROR;
}
wxThreadError wxThread::Resume()
{
+ wxCHECK_MSG( This() != this, wxTHREAD_MISC_ERROR,
+ _T("a thread can't resume itself") );
+
wxCriticalSectionLocker lock(m_critsect);
- if ( p_internal->GetState() == STATE_PAUSED )
- {
- m_critsect.Leave();
- p_internal->Resume();
- m_critsect.Enter();
+ wxThreadState state = m_internal->GetState();
- return wxTHREAD_NO_ERROR;
- }
- else
+ switch ( state )
{
- wxLogDebug(T("Attempt to resume a thread which is not paused."));
+ case STATE_PAUSED:
+ wxLogTrace(TRACE_THREADS, _T("Thread %ld suspended, resuming."),
+ GetId());
- return wxTHREAD_MISC_ERROR;
+ m_internal->Resume();
+
+ return wxTHREAD_NO_ERROR;
+
+ case STATE_EXITED:
+ wxLogTrace(TRACE_THREADS, _T("Thread %ld exited, won't resume."),
+ GetId());
+ return wxTHREAD_NO_ERROR;
+
+ default:
+ wxLogDebug(_T("Attempt to resume a thread which is not paused."));
+
+ return wxTHREAD_MISC_ERROR;
}
}
// exiting thread
// -----------------------------------------------------------------------------
-wxThread::ExitCode wxThread::Delete()
+wxThread::ExitCode wxThread::Wait()
+{
+ wxCHECK_MSG( This() != this, (ExitCode)-1,
+ _T("a thread can't wait for itself") );
+
+ wxCHECK_MSG( !m_isDetached, (ExitCode)-1,
+ _T("can't wait for detached thread") );
+
+ m_internal->Wait();
+
+ return m_internal->GetExitCode();
+}
+
+wxThreadError wxThread::Delete(ExitCode *rc)
{
- if (IsPaused())
- Resume();
+ wxCHECK_MSG( This() != this, wxTHREAD_MISC_ERROR,
+ _T("a thread can't delete itself") );
m_critsect.Enter();
- wxThreadState state = p_internal->GetState();
+ wxThreadState state = m_internal->GetState();
// ask the thread to stop
- p_internal->SetCancelFlag();
+ m_internal->SetCancelFlag();
+
+ if ( m_isDetached )
+ {
+ // detached threads won't broadcast about their termination by default
+ // because usually nobody waits for them - but here we do, so ask the
+ // thread to notify us
+ m_internal->Notify();
+ }
m_critsect.Leave();
switch ( state )
{
case STATE_NEW:
+ // we need to wake up the thread so that PthreadStart() will
+ // terminate - right now it's blocking on m_condRun
+ m_internal->SignalRun();
+
+ // fall through
+
case STATE_EXITED:
// nothing to do
break;
case STATE_PAUSED:
- // resume the thread first
- Resume();
+ // resume the thread first (don't call our Resume() because this
+ // would dead lock when it tries to enter m_critsect)
+ m_internal->Resume();
// fall through
default:
// wait until the thread stops
- p_internal->Wait();
+ m_internal->Wait();
+
+ if ( rc )
+ {
+ wxASSERT_MSG( !m_isDetached,
+ _T("no return code for detached threads") );
+
+ // if it's a joinable thread, it's not deleted yet
+ *rc = m_internal->GetExitCode();
+ }
}
- //GL: As we must auto-destroy, the destruction must happen here.
- delete this;
- return NULL;
+ return wxTHREAD_NO_ERROR;
}
wxThreadError wxThread::Kill()
{
- switch ( p_internal->GetState() )
+ wxCHECK_MSG( This() != this, wxTHREAD_MISC_ERROR,
+ _T("a thread can't kill itself") );
+
+ switch ( m_internal->GetState() )
{
case STATE_NEW:
case STATE_EXITED:
return wxTHREAD_NOT_RUNNING;
+ case STATE_PAUSED:
+ // resume the thread first
+ Resume();
+
+ // fall through
+
default:
-#ifdef HAVE_PTHREAD_CANCEL
- if ( pthread_cancel(p_internal->GetId()) != 0 )
+#ifdef HAVE_PTHREAD_CANCEL
+ if ( pthread_cancel(m_internal->GetId()) != 0 )
#endif
{
wxLogError(_("Failed to terminate a thread."));
return wxTHREAD_MISC_ERROR;
}
- //GL: As we must auto-destroy, the destruction must happen here (2).
- delete this;
+
+ if ( m_isDetached )
+ {
+ // if we use cleanup function, this will be done from
+ // PthreadCleanup()
+#if !HAVE_THREAD_CLEANUP_FUNCTIONS
+ ScheduleThreadForDeletion();
+
+ // don't call OnExit() here, it can only be called in the
+ // threads context and we're in the context of another thread
+
+ DeleteThread(this);
+#endif // HAVE_THREAD_CLEANUP_FUNCTIONS
+ }
+ else
+ {
+ m_internal->SetExitCode(EXITCODE_CANCELLED);
+ }
return wxTHREAD_NO_ERROR;
}
}
-void wxThread::Exit(void *status)
+void wxThread::Exit(ExitCode status)
{
- // first call user-level clean up code
+ wxASSERT_MSG( This() == this,
+ _T("wxThread::Exit() can only be called in the "
+ "context of the same thread") );
+
+ // from the moment we call OnExit(), the main program may terminate at any
+ // moment, so mark this thread as being already in process of being
+ // deleted or wxThreadModule::OnExit() will try to delete it again
+ ScheduleThreadForDeletion();
+
+ // don't enter m_critsect before calling OnExit() because the user code
+ // might deadlock if, for example, it signals a condition in OnExit() (a
+ // common case) while the main thread calls any of functions entering
+ // m_critsect on us (almost all of them do)
OnExit();
+ // now do enter it because SignalExit() will change our state
+ m_critsect.Enter();
+
// next wake up the threads waiting for us (OTOH, this function won't return
// until someone waited for us!)
- p_internal->SignalExit();
+ m_internal->SignalExit();
- p_internal->SetState(STATE_EXITED);
+ // leave the critical section before entering the dtor which tries to
+ // enter it
+ m_critsect.Leave();
+
+ // delete C++ thread object if this is a detached thread - user is
+ // responsible for doing this for joinable ones
+ if ( m_isDetached )
+ {
+ // FIXME I'm feeling bad about it - what if another thread function is
+ // called (in another thread context) now? It will try to access
+ // half destroyed object which will probably result in something
+ // very bad - but we can't protect this by a crit section unless
+ // we make it a global object, but this would mean that we can
+ // only call one thread function at a time :-(
+ DeleteThread(this);
+ }
- // delete both C++ thread object and terminate the OS thread object
- // GL: This is very ugly and buggy ...
-// delete this;
+ // terminate the thread (pthread_exit() never returns)
pthread_exit(status);
+
+ wxFAIL_MSG(_T("pthread_exit() failed"));
}
// also test whether we were paused
bool wxThread::TestDestroy()
{
- wxCriticalSectionLocker lock(m_critsect);
+ wxASSERT_MSG( This() == this,
+ _T("wxThread::TestDestroy() can only be called in the "
+ "context of the same thread") );
+
+ m_critsect.Enter();
- if ( p_internal->GetState() == STATE_PAUSED )
+ if ( m_internal->GetState() == STATE_PAUSED )
{
- // leave the crit section or the other threads will stop too if they try
- // to call any of (seemingly harmless) IsXXX() functions while we sleep
- m_critsect.Leave();
+ m_internal->SetReallyPaused(TRUE);
- p_internal->Pause();
+ // leave the crit section or the other threads will stop too if they
+ // try to call any of (seemingly harmless) IsXXX() functions while we
+ // sleep
+ m_critsect.Leave();
- // enter it back before it's finally left in lock object dtor
- m_critsect.Enter();
+ m_internal->Pause();
+ }
+ else
+ {
+ // thread wasn't requested to pause, nothing to do
+ m_critsect.Leave();
}
- return p_internal->WasCancelled();
+ return m_internal->WasCancelled();
}
wxThread::~wxThread()
{
+#ifdef __WXDEBUG__
m_critsect.Enter();
- if (p_internal->GetState() != STATE_EXITED &&
- p_internal->GetState() != STATE_NEW)
- wxLogDebug(T("The thread is being destroyed althought it is still running ! The application may crash."));
+
+ // check that the thread either exited or couldn't be created
+ if ( m_internal->GetState() != STATE_EXITED &&
+ m_internal->GetState() != STATE_NEW )
+ {
+ wxLogDebug(_T("The thread %ld is being destroyed although it is still "
+ "running! The application may crash."), GetId());
+ }
m_critsect.Leave();
+#endif // __WXDEBUG__
+
+ delete m_internal;
- delete p_internal;
// remove this thread from the global array
gs_allThreads.Remove(this);
+
+ // detached thread will decrement this counter in DeleteThread(), but it
+ // is not called for the joinable threads, so do it here
+ if ( !m_isDetached )
+ {
+ MutexLock lock(gs_mutexDeleteThread);
+ gs_nThreadsBeingDeleted--;
+
+ wxLogTrace(TRACE_THREADS, _T("%u scheduled for deletion threads left."),
+ gs_nThreadsBeingDeleted - 1);
+ }
}
// -----------------------------------------------------------------------------
{
wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect);
- return p_internal->GetState() == STATE_RUNNING;
+ return m_internal->GetState() == STATE_RUNNING;
}
bool wxThread::IsAlive() const
{
wxCriticalSectionLocker lock((wxCriticalSection&)m_critsect);
- switch ( p_internal->GetState() )
+ switch ( m_internal->GetState() )
{
case STATE_RUNNING:
case STATE_PAUSED:
{
wxCriticalSectionLocker lock((wxCriticalSection&)m_critsect);
- return (p_internal->GetState() == STATE_PAUSED);
+ return (m_internal->GetState() == STATE_PAUSED);
}
//--------------------------------------------------------------------
return FALSE;
}
- gs_mutexGui = new wxMutex();
-
gs_tidMain = pthread_self();
+#if wxUSE_GUI
+ gs_mutexGui = new wxMutex();
+
gs_mutexGui->Lock();
+#endif // wxUSE_GUI
+
+ // under Solaris we get a warning from CC when using
+ // PTHREAD_MUTEX_INITIALIZER, so do it dynamically
+ pthread_mutex_init(&gs_mutexDeleteThread, NULL);
return TRUE;
}
void wxThreadModule::OnExit()
{
- wxASSERT_MSG( wxThread::IsMain(), T("only main thread can be here") );
+ wxASSERT_MSG( wxThread::IsMain(), wxT("only main thread can be here") );
+
+ // are there any threads left which are being deleted right now?
+ size_t nThreadsBeingDeleted;
+ {
+ MutexLock lock(gs_mutexDeleteThread);
+ nThreadsBeingDeleted = gs_nThreadsBeingDeleted;
+ }
+
+ if ( nThreadsBeingDeleted > 0 )
+ {
+ wxLogTrace(TRACE_THREADS, _T("Waiting for %u threads to disappear"),
+ nThreadsBeingDeleted);
+
+ // have to wait until all of them disappear
+ gs_condAllDeleted->Wait();
+ }
// terminate any threads left
size_t count = gs_allThreads.GetCount();
if ( count != 0u )
- wxLogDebug(T("Some threads were not terminated by the application."));
+ {
+ wxLogDebug(wxT("%u threads were not terminated by the application."),
+ count);
+ }
for ( size_t n = 0u; n < count; n++ )
{
- // Delete calls the destructor which removes the current entry. We
- // should only delete the first one each time.
+ // Delete calls the destructor which removes the current entry. We
+ // should only delete the first one each time.
gs_allThreads[0]->Delete();
}
+#if wxUSE_GUI
// destroy GUI mutex
gs_mutexGui->Unlock();
delete gs_mutexGui;
+#endif // wxUSE_GUI
// and free TLD slot
(void)pthread_key_delete(gs_keySelf);
// global functions
// ----------------------------------------------------------------------------
+static void ScheduleThreadForDeletion()
+{
+ MutexLock lock(gs_mutexDeleteThread);
+
+ if ( gs_nThreadsBeingDeleted == 0 )
+ {
+ gs_condAllDeleted = new wxCondition;
+ }
+
+ gs_nThreadsBeingDeleted++;
+
+ wxLogTrace(TRACE_THREADS, _T("%u thread%s waiting to be deleted"),
+ gs_nThreadsBeingDeleted,
+ gs_nThreadsBeingDeleted == 1 ? "" : "s");
+}
+
+static void DeleteThread(wxThread *This)
+{
+ // gs_mutexDeleteThread should be unlocked before signalling the condition
+ // or wxThreadModule::OnExit() would deadlock
+ {
+ MutexLock lock(gs_mutexDeleteThread);
+
+ wxLogTrace(TRACE_THREADS, _T("Thread %ld auto deletes."), This->GetId());
+
+ delete This;
+
+ wxCHECK_RET( gs_nThreadsBeingDeleted > 0,
+ _T("no threads scheduled for deletion, yet we delete "
+ "one?") );
+ }
+
+ wxLogTrace(TRACE_THREADS, _T("%u scheduled for deletion threads left."),
+ gs_nThreadsBeingDeleted - 1);
+
+ if ( !--gs_nThreadsBeingDeleted )
+ {
+ // no more threads left, signal it
+ gs_condAllDeleted->Signal();
+
+ delete gs_condAllDeleted;
+ gs_condAllDeleted = (wxCondition *)NULL;
+ }
+}
+
void wxMutexGuiEnter()
{
- gs_mutexGui->Lock();
+#if wxUSE_GUI
+ gs_mutexGui->Lock();
+#endif // wxUSE_GUI
}
void wxMutexGuiLeave()
{
- gs_mutexGui->Unlock();
+#if wxUSE_GUI
+ gs_mutexGui->Unlock();
+#endif // wxUSE_GUI
}
#endif
projects / wxWidgets.git / blobdiff