MemoryMappedFile seems to be the only way to share memory between processes in .NET(?), however I didn't find a way to map a region to the process' virtual memory space, so it can't be really treated as a memory block since there's no way to get the pointer. I'm using pointer to process bitmap for best performance and reusability.
In c++ this can be easily achieved using boost.
Is there a way share a region of memory between processes and use pointer to read/write data?
For lower level access you can use MemoryMappedViewAccessor.SafeMemoryMappedViewHandle which returns a SafeMemoryMappedViewHandle which has a load of lower level access methods.
Here's an example:
static void Main()
{
// Open an MMF of 16MB (not backed by a system file; in memory only).
using var mmf = MemoryMappedFile.CreateOrOpen("mmfMapName", capacity: 16 * 1024 * 1024);
// Create an MMF view of 8MB starting at offset 4MB.
const int VIEW_BYTES = 8 * 1024 * 1024;
using var accessor = mmf.CreateViewAccessor(offset: 4 * 1024 * 1024, VIEW_BYTES);
// Get a pointer into the unmanaged memory of the view.
using var handle = accessor.SafeMemoryMappedViewHandle;
unsafe
{
byte* p = null;
try
{
// Actually get the pointer.
handle.AcquirePointer(ref p);
// As an example, fill the memory pointed to via a uint*
for (uint* q = (uint*)p; q < p + VIEW_BYTES; ++q)
{
*q = 0xffffffff;
}
}
finally
{
if (p != null)
handle.ReleasePointer();
}
}
}
using (var accessor = mmf.CreateViewAccessor(offset, length))- You can useaccessorto read and write value type items (which includes POCO structs) to and from the MMF at any offset.MemoryMappedViewAccessor.SafeMemoryMappedViewHandlewhich returns aSafeMemoryMappedViewHandlewhich has a load of lower level access methods. It even hasAcquirePointer(Byte*)which returns a pointer to the start of the MMF view - but that requiresunsafecode.