Toll-Free bridged in iOS development

The so-called toll-free bridging is a method or function that you can have in a frame

Use some types in both the core Foundatio and the foundation framework.

Many data types support this feature, including group and string data types.

The class and type descriptions for each frame will be toll-free bridged for an object.

And what object bridging should be described.

Type conversion keyword differences:

__bridge (equivalent to assign or managing objects yourself)

__bridge_transfer (equivalent to copy post release transfer of ownership of the object to others to manage)
__bridge_retained (equivalent to the reference count of the retain increment object)

Also be aware of the difference in the use of Arc when no arc and xcode4.2 are added.