In addition to the full set of format archetypes (attribute format style
arguments such as printf, scanf, strftime, and
strfmon), Darwin targets also support the CFString (or
__CFString__) archetype in the format attribute.
Declarations with this archetype are parsed for correct syntax
and argument types. However, parsing of the format string itself and
validating arguments against it in calls to such functions is currently
not performed.
Additionally, CFStringRefs (defined by the CoreFoundation headers) may
also be used as format arguments. Note that the relevant headers are only likely to be
available on Darwin (OSX) installations. On such installations, the XCode and system
documentation provide descriptions of CFString, CFStringRefs and
associated functions.