[progrium]

I guess I will look into this as that really sounds like syntactic sugar for something more basic. Like using the class.

I have a hard time keeping up with their changes but you might be right: https://developer.apple.com/documentation/foundation/nsautor...

Oddly it says you cannot use them directly, but later implies maybe they are just less efficient. It would be nice if somebody made an issue for this.

[pjscott]

The page you linked is not actually ambiguous, though perhaps a bit tricky to read. It says:

1. If you're compiling Objective C in ARC mode, you can't use NSAutoreleasePool directly, and must instead use @autoreleasepool.

2. In manual reference counting mode you can use either NSAutoreleasePool or @autoreleasepool, but the latter has lower overhead. (This may matter if e.g. you're draining the autorelease pool on every iteration of a loop to reduce memory spikes.)

Under the hood -- at least on the version I disassembled -- NSAutoreleasePool's -init and -release methods wrap the CoreFoundation CFAutoreleasePoolPush and CFAutoreleasePoolPop functions, which in turn call the runtime's objc_autoreleasePoolPush and objc_autoreleasePoolPop functions, which are the things that @autoreleasepool will cause the compiler to emit directly.

[lunixbochs]

This answer says the block is more efficient than manually managing NSAutoreleasePool objects: https://stackoverflow.com/a/12448176

This answer looks like a better overview of what the runtime is doing: https://stackoverflow.com/a/21010442

The @autoreleasepool block seems equivalent to this:

    ctx = _objc_autoreleasePoolPush()
    defer _objc_autoreleasePoolPop(ctx)

You could maybe provide sugar for it like this: https://play.golang.org/p/dljXN3BdEGr

[dolmen]

The implementation of your "sugar" can be shortened:

https://play.golang.org/p/8v4EL2B_c_t

[progrium]

Awesome, can you throw into an issue?

[lunixbochs]

Done https://github.com/progrium/macdriver/issues/12

[progrium]

wow, thanks!

[favorited]

Keep in mind that the reason the `@autorelease` syntax is faster is primarily due to ARC optimizations (which don't apply here, since you're not using ARC).

Calling the `_objc_autoreleasePoolXX` functions are still likely to be faster than the NSAutoreleasePool objects, but only because you're avoiding the Objective-C message sends.