Automatic Reference Counting (ARC) is a memory management feature of the Clangcompiler providing automatic reference counting for the Objective-C and Swiftprogramming languages. At compile time, it inserts into the object codemessagesretain and release^[1][2] which increase and decrease the reference count at run time, marking for deallocation those objects when the number of references to them reaches zero.

1. Nil Man Of The Year
2. Nil Mac Os Update
3. Mac Os Versions

(setq-default mac-right-option-modifier nil) 3.1.2 Define words using OS X Dictionary This layer by default enables defining words under point SPC x w d using OS X Dictionary. In some cases you might want to manually setup dictionary to use. With the SSL certificate and private key in the keychain and the device token on the pasteboard, you're ready to send some push notifications. Let's start by sending a notification using the Pusher app for Mac OS X. Open the Pusher Xcode project and run the PusherMac target.

ARC differs from tracing garbage collection in that there is no background process that deallocates the objects asynchronously at runtime.^[3] Unlike tracing garbage collection, ARC does not handle reference cycles automatically. This means that as long as there are 'strong' references to an object, it will not be deallocated. Strong cross-references can accordingly create deadlocks and memory leaks. It is up to the developer to break cycles by using weak references.^[4]

Apple Inc. deploys ARC in their operating systems, such as macOS (OS X) and iOS. Limited support (ARCLite)^[5] has been available since Mac OS X Snow Leopard and iOS 4, with complete support following in Mac OS XLion and iOS 5.^[6] Garbage collection was declared deprecated in OS X Mountain Lion, in favor of ARC, and removed from the Objective-C runtime library in macOS Sierra.^[7][8]

Objective-C[edit]

The following rules are enforced by the compiler when ARC is turned on:

• retain, release, retainCount, autorelease or dealloc cannot be sent to objects. Instead, the compiler inserts these messages at compile time automatically, including [super dealloc] when dealloc is overridden.^[9]
• Programs cannot cast directly between id and void *.^[9] This includes casting between Foundation objects and Core Foundation objects. Programs must use special casts, or calls to special functions, to tell the compiler more information about an object's lifetime.
• An autorelease pool can be used to allocate objects temporarily and retain them in memory until the pool is 'drained'. Without ARC, an NSAutoreleasePool object can be created for this purpose. ARC uses @autoreleasepool blocks instead, which encapsulate the allocation of the temporary objects and deallocates them when the end of the block is reached.^[9]
• Programs cannot call the functions NSAllocateObject and NSDeallocateObject^[9]
• Programs cannot use object pointers in C structures (structs)^[9]
• Programs cannot use memory zones (NSZone)^[9]
• To properly cooperate with non-ARC code, programs must use no method or declared property (unless explicitly choosing a different getter) that starts with new.^[9]

Property declarations[edit]

ARC introduces some new property declaration attributes, some of which replace the old attributes.

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1. ^ARCLite is ARC but without zeroing weak references (used when deploying to a less-capable operating environment than ARC requires).

Zeroing weak references[edit]

Zeroing weak references is a feature in Objective-C ARC that automatically clears (sets to nil) weak-reference local variables, instance variables, and declared properties immediately before the object being pointed to starts deallocating. This ensures that the pointer goes to either a valid object or nil, and avoids dangling pointers. Prior to the introduction of this feature, 'weak references' referred to references that were not retaining, but were not set to nil when the object they pointed to was deallocated (equivalent to unsafe_unretained in ARC), thus possibly leading to a dangling pointer. The programmer typically had to ensure that all possible weak references to an object were set to nil manually when it was being deallocated. Zeroing weak references obviates the need to do this.

Zeroing weak references are indicated by using the declared property attributeweak or by using the variable attribute __weak.

Zeroing weak references are only available in Mac OS X Lion (10.7) or later and iOS 5 or later, because they require additional support from the Objective-C runtime. However, some OS X classes do not currently support weak references.^[9] Code that uses ARC but needs to support versions of the OS older than those above cannot use zeroing weak references, and therefore must use unsafe_unretained weak references. There exists a third-party library called PLWeakCompatibility [1] that allows one to use zeroing weak references even on these older OS versions.

Converting to[edit]

Xcode 4.2 or later provides a way to convert code to ARC.^[10] As of Xcode 4.5, it is found by choosing Edit > Refactor > Convert to Objective-C ARC... Although Xcode will automatically convert most code, some code may have to be converted manually. Xcode will inform the developer when more complex use cases arise, such as when a variable is declared inside an autorelease pool and used outside it or when two objects need to be toll-free bridged with special casts.

Swift[edit]

In Swift, references to objects are strong, unless they are declared weak or unowned. Swift requires explicit handling of nil with the Optional type: a value type that can either have a value or be nil. An Optional type must be handled by 'unwrapping' it with a conditional statement, allowing safe usage of the value, if present. Conversely, any non-Optional type will always have a value and cannot be nil.

Accordingly, a strong reference to an object cannot be of type Optional, as the object will be kept in the heap until the reference itself is deallocated. A weak reference is of type Optional, as the object can be deallocated and the reference be set to nil. Unowned references fall in-between; they are neither strong nor of type Optional. Instead, the compiler assumes that the object to which an unowned reference points is not deallocated as long the reference itself remains allocated. This is typically used in situations where the target object itself holds a reference to the object that holds the unowned reference.

Swift also differs from Objective-C in its usage and encouragement of value types instead of reference types. Most types in the Swift standard library are value types and they are copied by value, whereas classes and closures are reference types and passed by reference. Because value types are copied when passed around, they are deallocated automatically with the reference that created them.^[11]

See also[edit]

References[edit]

1. ^Siracusa, John (July 20, 2011). 'Mac OS X 10.7 Lion: the Ars Technica review'. Ars Technica. Ars Technica. At section 'Automatic Reference Counting'. Retrieved November 17, 2016.CS1 maint: discouraged parameter (link)
2. ^Kochan, Stephen G. (2011). Programming in Objective-C (4th ed.). Boston, Mass.: Addison-Wesley. pp. 408. ISBN978-0321811905.
3. ^Hoffman, Kevin (2012). Sams teach yourself Mac OS X Lion app development in 24 hours. Indianapolis, Ind.: Sams. pp. 73. ISBN9780672335815.
4. ^'General'. Automatic Reference Counting. LLVM.org. Retrieved 15 August 2012.CS1 maint: discouraged parameter (link)
5. ^'Objective-C Feature Availability Index'. Apple, Inc. Retrieved 2013-10-14.CS1 maint: discouraged parameter (link)
6. ^Sakamoto, Kazuki (2012). Pro Multithreading and Memory Management for iOS and OS X with ARC, Grand Central Dispatch and Blocks. Apress. pp. xii. ISBN978-1430241164.
7. ^Siracusa, John (July 25, 2012). 'OS X 10.8 Mountain Lion: the Ars Technica review'. Ars Technica. At section 'Objective-C enhancements'. Retrieved November 17, 2016.
8. ^'Xcode 8 Release Notes'. Apple Developer. October 27, 2016. Archived from the original on March 19, 2017. Retrieved March 19, 2017.
9. ^ ^abcdefgh'Transitioning to ARC Release Notes'. Retrieved 14 September 2012.CS1 maint: discouraged parameter (link)
10. ^'What's New in Xcode 4.2 – Automatic Reference Counting'. Apple Inc. Archived from the original on 20 August 2012. Retrieved 3 October 2012.CS1 maint: discouraged parameter (link)
11. ^'Value and Reference Types'. Apple Developer. August 15, 2014. Retrieved November 17, 2016.

External links[edit]

• 'Automatic Reference Counting' in The Swift Programming Language

Minimalist Sublime Text 2 UI dark and light themes and color schemes. Includes HDPI support for retina displays. (Unmaintained)

Details

Installs

• Total50K
• Win29K
• Mac13K
• Linux8K

Readme

Source

raw.​githubusercontent.​com

Nil Theme

Nil UI theme for Sublime Text 2

Nil is the dark theme for the overall Nil theme package. Yes, there'sa light theme – scroll down if that's what you want. They're both inthe same repository, though they have different names just to be fancy.The color scheme pictured above is Big Duo.

This theme is based on Raik Ilves's Pseudo OSXtheme, which is in turnbased on Ian Hill's Soda theme. Additionally, this theme was inspired by Liam Cain's Refreshtheme, which is alsoa variant of Pseudo OSX. So, it's worth noting that Raik's made a prettyhandy base for new themes.I recommend checking out both of them if thisdoesn't do it for you (and it's rough around the edges, so it may not).

Overlay scrollbars are kindly borrowed from the default theme.

Ayin Theme

Ayin UI theme for Sublime Text 2

Ayin is the light theme of the Nil theme package. It features a lot ofgrey and arguably softer colors, though should still remain as pseudo-functional as its dark counterpart. The color scheme pictured above isTubnil Bright.

Color Schemes

The Nil theme package comes with the two color schemes seen in the boththe light and dark screenshots respectively:

• Tubnil.tmTheme → My personal variation of the Tubster theme forTextMate. This is the original dark color scheme.

• Tubnil Bright.tmTheme → A variation on the above Tubnil theme forfolks who like bright color schemes.

• Big Duo.tmTheme → Another variation on Tubnil, this time witha slightly lighter background color, arguably less intense colors,and so on. Cast in the name of god and all that.

Both can be found in the root directory of the package, so to use iteither, simply point your color_scheme preference toTheme - Nil/Tubnil.tmTheme or one of the other color schemes.

Options

There are a handful of options you can use to customize the appearanceof both the Nil and Ayin themes. All options are boolean values anddisabled by default. Their keys and descriptions follow:

• highlight_modified_tabs — If true, will display an orange bar undertabs with modified buffers.
• sidebar_folders — If true, will display a folder icon beside foldersin the sidebar instead of a disclosure triangle. Sidebar folders areoff by default.
• colored_folder_glyphs — If true, will tint either folder icons ordisclosure triangles in the sidebar (only the sidebar) purple.
• disable_colored_group_labels — If true, will disable the coloredgroup labels. Group labels are the things that say “Group 1” and 2 andso on in the sidebar. They're only visible if you have open filesshown. Colored group labels are enabled by default.
• disable_colored_folder_labels — If true, will disable the coloredfolder labels in the sidebar. This is independent of group labelcoloring. Colored folder labels are enabled by default.

To set any of these properties, place them and their values in your userpreferences file.

HDPI Displays

This theme includes HDPI images for displays that support HDPI on MacOS X, such as the recent (as of this writing) MacBook Pro with theretina display. Both screenshots above are in HDPI.

Fonts

In the above screenshots, the font in use is PragmataPro, designed byFabrizio Schiavi. In previous screenshots, the font in use was Envy Code R,by Damien Guard. The former is an excellent font, but is not free. Thelatter is also an excellent font and free. Neither font ships with thistheme package. My personal preference these days is PragmataPro, but Ihad no particular font choice in mind for the theme and the importantthing is that you use what you like.

Installation

Package Control

If you have Package Control installed, you simply need to open thePackage Install window and select “Theme - Nil”. After that, skip aheadto the “Activating” section of this README.

Installation via Git

You can download or clone the repository into your Sublime Text 2Packages directory. To do this, simply navigate to~/Library/Application Support/Sublime Text 2/Packages (or wherever itis on your particular operating system) and run the following command:

It's very important you clone the repository into the Theme - Nildirectory otherwise the theme won't locate its assets and will take onan eldritch appearance. You don't want Shub-Niggurath crawlingout of your screen, so remember, put it in the right directory.

Nil Mac Os Update

Manually Downloading

If you choose to download an archive of this repo from GitHub, you mustrename the extracted folder to Theme - Nil and put it in yourPackages directory. That's it – simple.

Activating

Mac Os Versions

In your Settings - User file (hit ⌘, on Mac OS to open it), set the'theme' key to 'Nil.sublime-theme' or 'Ayin.sublime-theme', likeso:

or

Assuming you have then installed it correctly, it should show the theme.Due to what I assume is settings from previous themes surviving, you maywish to restart Sublime Text 2 as well, but otherwise you should be goodto go.