A pointer to an Objective-C foreign object.
A selector of type
sel
.
A string or
nil
.
A pointer to an Objective-C foreign object or
nil
.
A notification center.
The function
add-observer
calls the Objective-C instance method
"addObserver:selector:name:object:"
of
centre
to add
target
as an observer for
selector
with the given
name
and
object
, which both default to
nil
.
If center is omitted then it defaults to the default notification center.