The Windows Driver Kit (WDK) provides build environments to produce the following builds:
Checked (debug) builds to use during development.
Free (release) builds that generate the final versions of your code.
By default, the WDK build environment enables code optimization in a free build and disables code optimizations in a checked build.
It is rare that you would disable code optimizations in a free build. However, this macro is useful if you need to disable code optimizations in just one part of a large project.
For example, you can specify the following macro in your Sources file to disable code optimization on 386 platforms:
Note If you plan to do source-level debugging, use a checked build, which disables code optimization. Debugging optimized code can be extremely difficult.
Build date: 5/3/2011