Format Checks Specific to Particular Target Machines

For some target machines, GCC supports additional options to the format attribute (see Declaring Attributes of Functions).

Solaris Format Checks

Solaris targets support the cmn_err (or __cmn_err__) format check. cmn_err accepts a subset of the standard printf conversions, and the two-argument %b conversion for displaying bit-fields. See the Solaris man page for cmn_err for more information.

Darwin Format Checks

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.