NSValue
http://developer.apple.com/documentation/Cocoa/Reference/Foundation/Classes/NSValue_Class/
An NSValue object serves as an object wrapper for a standard C or Objective-C data item, allowing it to be stored in a collection object such as an NSArray or NSDictionary.
NSValue is NOT a property list format - you can't write one to disk in NSUserDefaults, for example. Use the various NSStringFrom foundation functions to do this. (NSNumber, a subclass of NSValue, IS a property list format.)
ObjectiveC/4objc_runtime_overview/chapter_4_section_6.html has a list of the return types for objCType, to determine the type of data a NSValue contains.
The above link is no longer working. ObjectiveC/Articles/chapter_13_section_9.html appears to be the new location. Probably a better practice to just use @encode() anyway, I'd assume.
What's the difference between these two creation methods?
+ (NSValue )value:(const void )value withObjCType:(const char )type;
+ (NSValue )valueWithBytes:(const void )value objCType:(const char )type;
The documentation for the two are nearly identical, save for the second that has this very odd line "This method is equivalent to value:withObjCType:, which is part of Cocoa. "
GNUstep docs say the second one is a " Synonym for value:withObjCType:." I dunno...
These functions are identical. In fact the first one calls the second one, which makes valueWithBytes perform better :-)
