Open32 is designed to work with PM-compatible text mode applications (such as those marked as WINDOWCOMPAT). As with native OS/2 applications, however, a text mode Open32 application is restricted to a limited set of Open32 and PM functions (no GDI and few user functions). Also, as with native OS/2 applications, pure text mode applications (those marked as NOWINDOWCOMPAT) are prohibited from calling any Open32 functions (as well as PM functions). Calls to any Open32 function from an application before PM is initialized are currently defined to produce unpredictable behavior.