Apps Write to shared memory?

[TheRealCeeBee]

Hey All,

Just nutting out some layouts on my pc, for use in transmitting to a serial screen later over USB, all sems to be going well enough. but.
The dll found on the web lists a bunch of calls that can be read... but I cannot find much info on writes?

Can one for example on my serial screen (touch enabled) have a button press send a "start car" signal to the shared mem?
enable drs, ers etc etc..

I am working in C# for now as eventual deployment will be to an RPi with win10_IOT.

TIA.