Sent to all top-level windows when the system detects more than 12.5 percent of system time over a 30- to 60-second interval is being spent compacting memory. This indicates that system memory is low.
A window receives this message through its WindowProc function.
The ratio of central processing unit (CPU) time currently spent by the system compacting memory to CPU time currently spent by the system performing other operations. For example, 0x8000 represents 50 percent of CPU time spent compacting memory.
This parameter is not used.
If an application processes this message, it should return zero.
When an application receives this message, it should free as much memory as possible, taking into account the current level of activity of the application and the total number of applications running on the system.
Minimum supported client
|Windows 2000 Professional [desktop apps only]|
Minimum supported server
|Windows 2000 Server [desktop apps only]|