Windows CE中的内存不足通知

Question

Is there a way to get notifications when the available memory goes below a certain limit (user configurable)? I have looked into the WM_HIBERNATE event but it seems the limit for this event is not user configurable and is hard-coded (160KB??). The only way I can think of is to poll the OS periodically (every 5 seconds??) for available memory through GlobalMemoryStats() API and if the available memory goes below the user configured limit then raise an event to the user. Is there a better way?

This notification has to work on devices starting with Windows CE 5.0 & Windows Mobile 6.5

Answer 1

There's nothing inherent in the OS that's going to tell you that memory is below an arbitrary level, no. Either polling in your app or creating a service/driver that does it for you is probebly the best way. Which is "better" would depend on if only one process needs to know about the notification.

Answer 2

If thats your application that can drain memory, then you can implement some code to intercept such low memory situations before system will do it. Some hints:

• override your new, malloc or any other function that allocates memory and check each time if allocation will drain your memory.

• if you are afraid you will slow down your app (and you should:)) then use some memory manager, like Dougs Lee malloc.c, you can modify is so each time it grabs another 64KB block from system memory you will check if system memory is not too low

• you can read from registry what are the low memory levels, you will find these entries under: HKLM\\System\\Hibernate for WCE and HKLM\\System\\OOM for WM.

http://msdn.microsoft.com/en-us/library/ms911907.aspx