Question

There’s information my program has to send from one part to another, such as from DragEnter to GiveFeedback to change the cursor. This is easily done with a variable as a flag. However – what if the user starts several instances of the program?

One way would be to write information to a file, but it seems best to do as little disk operations as possible. Another way would be to use pipes, but it seems a bit complicated if there are many instances of the program. Is there another way?

Answer 1

Take a look at memory mapped files.

A memory-mapped file contains the contents of a file in virtual memory. This mapping between a file and memory space enables an application, including multiple processes, to modify the file by reading and writing directly to the memory.