Wednesday, November 24, 2010

Virtual Key Code to String

If you ever used GetAsyncKeyState() or GetKeyState() or any other windows function using virtual keys, this post might be useful to you.

There are certain situations where you might want to print out a string representation of the virtual key you're dealing with, and from what I've researched, I don't think there's an API function call that will do this for us, so I made my own.

The following function will take as input a Virtual Key Code (e.g. VK_RETURN) and then return the string representation of the key (e.g. "VK_RETURN"). Of course it works for 'A' to 'Z' and digits as well (there are no VK_* macros for such virtual keys because they're the same as the ascii char representation).

Here's the function, Its a big one so I've hidden it by default.
Show Code


I ended up needing this on my NES emulator in order to display mapped-keyboard settings. That's probably where other people will need it too.


In case you've never seen something like this and you're wondering how it works, it uses a powerful and very useful feature of the C/C++ preprocessor called 'stringification'.

Essentially you take convert arguments to a macro into string representations.
Here's more info:
http://gcc.gnu.org/onlinedocs/cpp/Stringification.html

I took the winapi macros for the virtual keys and wrapped them in a macro that converts them to strings. Mostly was just copy-paste and regex replace work.
Anyways have fun :)

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