Manpages - rtcSetDeviceMemoryMonitorFunction.3embree3

  rtcSetDeviceMemoryMonitorFunction - registers a callback function
    to track memory consumption

  #include <embree3/rtcore.h>

  typedef bool (*RTCMemoryMonitorFunction)(
    void* userPtr,
    ssize_t bytes,
    bool post
  );

  void rtcSetDeviceMemoryMonitorFunction(
    RTCDevice device,
    RTCMemoryMonitorFunction memoryMonitor,
    void* userPtr
  );

Using the rtcSetDeviceMemoryMonitorFunction call, it is possible to register a callback function (memoryMonitor argument) with payload (userPtr argument) for a device (device argument), which is called whenever internal memory is allocated or deallocated by objects of that device. Using this memory monitor callback mechanism, the application can track the memory consumption of an Embree device, and optionally terminate API calls that consume too much memory.

Only a single callback function can be registered per device, and further invocations overwrite the previously set callback function. Passing NULL as function pointer disables the registered callback function.

Once registered, the Embree device will invoke the memory monitor callback function before or after it allocates or frees important memory blocks. The callback function gets passed the payload as specified at registration time (userPtr argument), the number of bytes allocated or deallocated (bytes argument), and whether the callback is invoked after the allocation or deallocation took place (post argument). The callback function might get called from multiple threads concurrently.

The application can track the current memory usage of the Embree device by atomically accumulating the bytes input parameter provided to the callback function. This parameter will be >0 for allocations and <0 for deallocations.

Embree will continue its operation normally when returning true from the callback function. If false is returned, Embree will cancel the current operation with the RTC_ERROR_OUT_OF_MEMORY error code. Issuing multiple cancel requests from different threads is allowed. Canceling will only happen when the callback was called for allocations (bytes > 0), otherwise the cancel request will be ignored.

If a callback to cancel was invoked before the allocation happens (post = false=), then the bytes parameter should not be accumulated, as the allocation will never happen. If the callback to cancel was invoked after the allocation happened (post = true=), then the bytes parameter should be accumulated, as the allocation properly happened and a deallocation will later free that data block.

On failure an error code is set that can be queried using rtcGetDeviceError.

[rtcNewDevice]