标签：http 使用 os io for 问题 cti ar
最近碰到了CFObject和NSObject转换的问题，由于ARC不能管理Core Foundation Object的生命周期，所以在Core Foundation和ARC之间，我们需要使用到__bridge,__bridge_retained和__bridge_transfer三个转换关键字。
__bridge transfers a pointer between Objective-C and Core Foundation with no transfer of ownership.
__bridge_retained or CFBridgingRetain casts an Objective-C pointer to a Core Foundation pointer and also transfers ownership to you.
You are responsible for calling CFRelease or a related function to relinquish ownership of the object.
__bridge_transfer or CFBridgingRelease moves a non-Objective-C pointer to Objective-C and also transfers ownership to ARC.
ARC is responsible for relinquishing ownership of the object.
意思就是:
__bridge只做类型转换，但是不修改对象（内存）管理权；
__bridge_retained（也可以使用CFBridgingRetain）将Objective-C的对象转换为Core Foundation的对象，同时将对象（内存）的管理权交给我们，后续需要使用CFRelease或者相关方法来释放对象；
__bridge_transfer（也可以使用CFBridgingRelease）将Core Foundation的对象转换为Objective-C的对象，同时将对象（内存）的管理权交给ARC。
__bridge,__bridge_retained和__bridge_transfer的意思，区别与使用,布布扣,bubuko.com
__bridge,__bridge_retained和__bridge_transfer的意思，区别与使用
标签：http 使用 os io for 问题 cti ar
原文地址：http://www.cnblogs.com/xiaochaozi/p/3890254.html
