Environment > Setting Preferences > Windows Runtime Preferences

# Windows Runtime Preferences

These preferences exist to support the use of IDL runtime and the IDL Virtual Machine under Microsoft Windows. They are not present in non-Windows versions of IDL.o

Under Microsoft Windows, the `idlrt.exe` program runs runtime or virtual-machine applications. The preferences described here provide default values for parameters to that program if they are not explicitly provided.

If IDL finds an IDL preference file named `idl.pref` in the directory containing the IDL DLL, IDL treats it as a command-line preference file and automatically reads and processes it. This is the most likely way in which the preferences specified in this section are used.

## IDL_WINRT_FILE

If you run `idlrt.exe` without specifying an IDL SAVE file, the IDL_WINRT_FILE preference supplies the name of the file to use.

Committed changes take effect at the next `idlrt.exe` invocation. The default value is an empty string ('').

This preference cannot be set in the IDL Workbench Preferences dialog.

## IDL_WINRT_FILE_TYPE

If you run `idlrt.exe` without specifying the licensing mode under which it is expected to run, the IDL_WINRT_FILE_TYPE preference supplies the mode.

Value | Alias
0 | Runtime
1 | EmbeddedRuntime
2 | VirtualMachine

Committed changes take effect at the next `idlrt.exe` invocation. The default value is Runtime (0).

This preference cannot be set in the IDL Workbench Preferences dialog.

## IDL_WINRT_ICON

The IDL_WINRT_ICON preference specifies the file containing the icon to use with a runtime or virtual-machine application.

Committed changes take effect at the next `idlrt.exe` invocation. The default value is an empty string (''), indicating that the standard IDL icon should be used.

This preference cannot be set in the IDL Workbench Preferences dialog.