DOC: Freeing Allocated Resources with IoAssignResources()

The information in this article applies to:

• Microsoft Win32 DDK (Device Development Kit) for Windows NT, version 3.51

SUMMARY

The Microsoft Win32 DDK version 3.51 online documentation incorrectly states that a device driver must call the IoAssignResources() function with a RequestedResources list specifying zero as the IO_RESOURCE_REQUIREMENTS_LIST's ListSize value to erase its claim on resources. The correct way for a driver to erase its claim on resources is to call the IoAssignResources() function with a value of NULL for the RequestedResources parameter.

MORE INFORMATION

A device driver should use the same API function to free resources that it used to allocate them. If the IoAssignResources() function is used to allocate resources, the IoAssignResources() function should be used to free them. If the IoReportResourceUsage() function is used to allocate resources, the IoReportResourceUsage() function should be used to free them. Note that these two API functions use different methods of freeing the resources they have claimed.

A caller of the HalAssignSlotResources() function should use the IoAssignResources() function to free the resources it claimed because this API function internally calls the IoAssignResources() function.

This documentation error has been corrected in the Windows NT DDK version 4.0 online documentation.