Windows class names are case insensitive. OS/2 class names are case sensitive. Open32 converts class names to uppercase before registering them with OS/2. In general, Open32 that deal with class names work as expected, with respect to Windows; for example, GetClassInfo returns the class name exactly as it was originally registered. One important difference occurs with resource files, however. Open32 does not currently support Windows resources; Open32 resources are really OS/2 resources. If an Open32 resource contains a user-defined class, the class name must be converted to uppercase because that it how the class is registered internally with OS/2.