Prints a description of a Core Foundation object to stderr.


func CFShow(_ obj: CFTypeRef!)



A Core Foundation object derived from CFType. If obj is not a Core Foundation object, an assertion is raised.


The output is printed to the standard I/O standard error (stderr).

This function is useful as a debugging aid for Core Foundation objects. Because these objects are based on opaque types, it is difficult to examine their contents directly. However, the opaque types implement description function callbacks that return descriptions of their objects. This function invokes these callbacks.

Special Considerations

You can use CFShow in one of two general ways. If your debugger supports function calls (such as gdb does), call CFShow in the debugger:

(gdb) call (void) CFShow(string)
Hello World

You can also incorporate calls to CFShow in a test version of your code to print out "snapshots" of Core Foundation objects to the console.

See Also

Miscellaneous Functions

func CFCopyDescription(CFTypeRef!) -> CFString!

Returns a textual description of a Core Foundation object.

func CFCopyTypeIDDescription(CFTypeID) -> CFString!

Returns a textual description of a Core Foundation type, as identified by its type ID, which can be used when debugging.

func CFGetTypeID(CFTypeRef!) -> CFTypeID

Returns the unique identifier of an opaque type to which a Core Foundation object belongs.