+GType designators are singleton structures meaning that for every GType, there may be only one GType designator structure for it; this means that two GType designators are equal (with respect to the @code{COMMON-LISP:EQ} function) if and only if their corresponding GTypes are the same.
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+GType designators remain the same (with respect to the @code{COMMON-LISP:EQ} function) even after dumping and restarting Lisp memory image.
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+GType designators are obtained with @ref{gtype} function, and corresponding numeric and string values are accessed via @ref{gtype-id} and @ref{gtype-name} functions (you must not access @code{gtype} structure directly). If an attempt is made to obtain an invalid GType, then a warning is signalled but GType designator is still returned (which may become valid at some later time due to e.g. library being initialized).