An environment variable contains information about an aspect of the operating system (OS) environment, such as a drive, path, or configuration string.
When you create a new OS environment with Microsoft® Platform Builder, the integrated development environment (IDE) sets specific environment variables based on the platform settings you select. Once you complete the creation process, you can set or unset the environment variables from a command prompt build window, a batch file, any application in the execution path, or in the IDE itself.