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refdescriptor — A description of the topic of a reference page
refdescriptor ::= (#PCDATA|action|application|classname|methodname|interfacename|exceptionname|ooclass|oointerface|ooexception|package|command|computeroutput|database|envar|errorcode|errorname|errortype|errortext|filename|function|guibutton|guiicon|guilabel|guimenu|guimenuitem|guisubmenu|hardware|interface|keycap|keycode|keycombo|keysym|literal|code|constant|markup|medialabel|menuchoice|mousebutton|option|optional|parameter|prompt|property|replaceable|returnvalue|sgmltag|structfield|structname|symbol|systemitem|uri|token|type|userinput|varname|nonterminal)*
               Reference pages (RefEntrys) are usually identified
               by a short, succinct topic name, such as the name of a function
               or command.  The RefName (or one of the
               RefNames, in the case of a reference page that has
               several) is generally used as the topic name.  When none of the
               RefNames is appropriate, RefDescriptor
               is used to specify the topic name.
               
            
               RefDescriptor is unnecessary when an appropriate
               RefName can be selected automatically.  At least one
               RefName is required, so RefDescriptor cannot
               be used in place of a name, only in addition to it.
               
            
May be formatted inline or as a displayed block, depending on context.
                  Formatting reference pages may require a fairly sophisticated
                  processing system.  Much of the meta-information about a
                  reference page (its name, type, purpose, title, and
                  classification) is stored in wrappers near the beginning of
                  the RefEntry.
                  
               
Common presentational features, such as titles and running heads, may require data from several of these wrappers plus some generated text. Other formatting often requires that these elements be reordered.
                  If a RefDescriptor is present, it should be used
                  for the short topic name.  This name usually appears in the running
                  header along with the ManVolNum in print media.
                  It may also appear in tables of contents and the index.
                  
               
                  
                  The InterfaceDefinition
                  element will be discarded in DocBook V4.0. It will no longer be available
                  in the content model of this element.
                  
               
The following elements occur in refdescriptor:
                  action, application, classname, code, command, computeroutput, constant, database, email, envar, errorcode, errorname, errortext, errortype, exceptionname, filename, function, guibutton, guiicon, guilabel, guimenu, guimenuitem, guisubmenu, hardware, interface, interfacename, keycap, keycode, keycombo, keysym, literal, markup, medialabel, menuchoice, methodname, mousebutton, nonterminal, ooclass, ooexception, oointerface, option, optional, package, parameter, prompt, property, replaceable, returnvalue, sgmltag, structfield, structname, symbol, systemitem, token, type, uri, userinput, varname.