RegisterOOMNotification (Compact 2013)

Article
08/12/2016

3/28/2014

This function is used to enable event handles to receive out-of-memory (OOM) notifications.

Syntax

BOOL RegisterOOMNotification (
   PHANDLE phMemLow,
   PHANDLE phMemPressure,
   PHANDLE phMemHealthy
);

Parameters

phMemLow
[in] Pointer to a handle to receive the event handle of the manual-reset event that will be signaled when memory is low.

phMemPressure
[in] Pointer to a handle to receive the event handle of the manual-reset event that will be signaled when memory is under pressure.

phMemHealthy
[in] Pointer to a handle to receive the event handle of the manual-reset event that will be signaled when memory is in a healthy state, which is above the healthy threshold.

Return Value

Returns a nonzero value if successful; otherwise, fails.

Remarks

The caller is responsible for closing the handles. All of the handles returned are wait-only handles where the caller can only call WaitForSingleObject or WaitForMultipleObjects on these handles.

Example

The following example code illustrates how to use this function in a custom OOM handler.

HANDLE hMemLow, hMemPressure, hMemHealthy;
// get OOM notification event
if (RegisterOOMNotification (&hMemLow, &hMemPressure, &hMemHealthy) {

   HANDLE hEvts[2] = { hMemLow, hMemPressure};
   while (g_bHandleOOM) {
      // wait for OOM notifications
      DWORD dwWaitResult = WaitForMultipleObjects (2, hEvts, FALSE, INFINITE);

      // try to free memory based on the OOM event, until 
      // memory is healthy again.
      do {
         // try to free memory, typically done by closing applications
         // depending on the wait result.
         if (!TryToFreeMemory (dwWaitResult)) {
            // can’t free more memory. Block and hope for someone
            // else to release memory. Or you can choose to reboot
            // the device here as memory is low and couldn't recover.
            WaitForSingleObject (hMemHealthy, INFINITE);
         }
      } while (WaitForSingleObject (hMemHealthy, 0) != WAIT_OBJECT_0);
   }
   CloseHandle (hMemLow);
   CloseHandle (hMemPressure);
   CloseHandle (hMemHealthy);
}

Requirements

Header

pkfuncs.h

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