The reader generic functions which simply return information associated with slot definition metaobjects are presented together here in the format described in Section 29.3.3, “Introspection: Readers for class metaobjects”.

Each of the reader generic functions for slot definition metaobjects has the same syntax, accepting one required argument called slot, which must be a slot definition metaobject; otherwise, an ERROR is SIGNALed. An ERROR is also SIGNALed if the slot definition metaobject has not been initialized.

These generic functions can be called by the user or the implementation.

For any of these generic functions which returns a list, such lists will not be mutated by the implementation. The results are undefined if a portable program allows such a list to be mutated.

A slot definition metaobject can be created by calling MAKE-INSTANCE. The initialization arguments establish the definition of the slot definition. A slot definition metaobject cannot be redefined; calling REINITIALIZE-INSTANCE SIGNALs an ERROR.

Initialization of a slot definition metaobject must be done by calling MAKE-INSTANCE and allowing it to call INITIALIZE-INSTANCE. Portable programs must not...

Since metaobject classes may not be redefined, no behavior is specified for the result of calls to UPDATE-INSTANCE-FOR-REDEFINED-CLASS on slot definition metaobjects. Since the class of a slot definition metaobject cannot be changed, no behavior is specified for the result of calls to UPDATE-INSTANCE-FOR-DIFFERENT-CLASS on slot definition metaobjects.

During initialization, each initialization argument is checked for errors and then associated with the slot definition metaobject. The value can then be accessed by calling the appropriate accessor as shown in Table 29.3, “Initialization arguments and accessors for slot definition metaobjects”.

This section begins with a description of the error checking and processing of each initialization argument. This is followed by a table showing the generic functions that can be used to access the stored initialization arguments.

In these descriptions, the phrase “this argument defaults to value” means that when that initialization argument is not supplied, initialization is performed as if value had been supplied. For some initialization arguments this could be done by the use of default initialization arguments, but whether it is done this way is not specified. Implementations are free to define default initialization arguments for specified slot definition metaobject classes. Portable programs are free to define default initialization arguments for portable subclasses of the class CLOS:SLOT-DEFINITION.

After the processing and defaulting of initialization arguments described above, the value of each initialization argument is associated with the slot definition metaobject. These values can then be accessed by calling the corresponding generic function. The correspondences are as follows: