Shared Memory Overview

The RTSS shared memory object is a region of non-paged physical memory that can be mapped into the virtual address space of a process. When a shared memory object has a name, additional processes may map the region of memory. A shared memory object is accessed with both a handle and a virtual address. In order for a process to completely end its access to a shared memory object it must close the handle. When all processes end their access to a shared memory object, the following occurs:

• The memory region is returned to the pool of non-paged kernel memory.
• The object ceases to exist.

Environments

The RTSS shared memory object is always maintained in the RTSS environment. However, Win32 processes may create and open RTSS shared memory objects.

The RTSS shared memory object is its own named object. The RtCreateSharedMemory and RtOpenSharedMemory calls implicitly map the shared memory; this eliminates the explicit Win32 call to the MapViewOfFile call. When the shared memory object is created, RTSS backs the shared memory object with non-paged memory.