




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