The custom object snap manager handles the registration of custom object snap modes. It can be used to add, remove, activate, and deactivate custom object snap modes. The custom object snap manager also can be used to query whether a specified object snap mode is registered and active.
There is a single custom object snap manager for the entire application. Once registered, a custom object snap mode can be applied in any open document. The following global function can be used to access the custom object snap manager:
AcDbCustomOsnapManager * acdbCustomOsnapManager() const;
Typically, custom object snap modes are registered when the application is first loaded and are removed when the application is unloaded, although they can be registered and removed at any time.