<p>For example VK_LEFT, VK_DELETE, VK_ESCAPE, VK_RETURN, etc. How and where are they declared? Are they constants, #defines, or something else? Where do they come from?</p>

<p>If possible, please provide a file name/path where they are declared. Or some other info as specific as possible.</p>

These are declared using
```
#define
```
in the file
```
winuser.h
```
in the Platform SDK. In my installation of Visual Studio 2008, the full path is
```
```
C:\Program Files\Microsoft SDKs\Windows\v6.0A\Include\WinUser.h
```
```