P'Library_Level
, where P is an entity name,
returns a Boolean value which is True if the entity is declared
at the library level, and False otherwise. Note that within a
generic instantiation, the name of the generic unit denotes the
instance, which means that this attribute can be used to test
if a generic is instantiated at the library level, as shown
in this example:
generic ... package Gen is pragma Compile_Time_Error (not Gen'Library_Level, "Gen can only be instantiated at library level"); ... end Gen;