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| <ol class="chapter"><li class="chapter-item expanded "><a href="introduction.html"><strong aria-hidden="true">1.</strong> Introduction</a></li><li class="chapter-item expanded "><a href="requirements.html"><strong aria-hidden="true">2.</strong> Requirements</a></li><li class="chapter-item expanded "><a href="library-usage.html"><strong aria-hidden="true">3.</strong> Library Usage with build.rs</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="tutorial-0.html"><strong aria-hidden="true">3.1.</strong> Tutorial</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="tutorial-1.html"><strong aria-hidden="true">3.1.1.</strong> Add bindgen as a Build Dependency</a></li><li class="chapter-item expanded "><a href="tutorial-2.html"><strong aria-hidden="true">3.1.2.</strong> Create a wrapper.h Header</a></li><li class="chapter-item expanded "><a href="tutorial-3.html"><strong aria-hidden="true">3.1.3.</strong> Create a build.rs File</a></li><li class="chapter-item expanded "><a href="tutorial-4.html"><strong aria-hidden="true">3.1.4.</strong> Include the Generated Bindings in src/lib.rs</a></li><li class="chapter-item expanded "><a href="tutorial-5.html"><strong aria-hidden="true">3.1.5.</strong> Write a Sanity Test</a></li><li class="chapter-item expanded "><a href="tutorial-6.html"><strong aria-hidden="true">3.1.6.</strong> Publish Your Crate!</a></li></ol></li><li class="chapter-item expanded "><a href="non-system-libraries.html"><strong aria-hidden="true">3.2.</strong> Bindings for non-system libraries</a></li></ol></li><li class="chapter-item expanded "><a href="command-line-usage.html"><strong aria-hidden="true">4.</strong> Command Line Usage</a></li><li class="chapter-item expanded "><a href="customizing-generated-bindings.html"><strong aria-hidden="true">5.</strong> Customizing the Generated Bindings</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="allowlisting.html"><strong aria-hidden="true">5.1.</strong> Allowlisting</a></li><li class="chapter-item expanded "><a href="blocklisting.html"><strong aria-hidden="true">5.2.</strong> Blocklisting</a></li><li class="chapter-item expanded "><a href="opaque.html"><strong aria-hidden="true">5.3.</strong> Treating a Type as an Opaque Blob of Bytes</a></li><li class="chapter-item expanded "><a href="replacing-types.html"><strong aria-hidden="true">5.4.</strong> Replacing One Type with Another</a></li><li class="chapter-item expanded "><a href="nocopy.html"><strong aria-hidden="true">5.5.</strong> Preventing the Derivation of Copy and Clone</a></li><li class="chapter-item expanded "><a href="nodebug.html"><strong aria-hidden="true">5.6.</strong> Preventing the Derivation of Debug</a></li><li class="chapter-item expanded "><a href="nodefault.html"><strong aria-hidden="true">5.7.</strong> Preventing the Derivation of Default</a></li><li class="chapter-item expanded "><a href="must-use-types.html"><strong aria-hidden="true">5.8.</strong> Annotating types with #[must-use]</a></li><li class="chapter-item expanded "><a href="visibility.html"><strong aria-hidden="true">5.9.</strong> Field visibility</a></li><li class="chapter-item expanded "><a href="code-formatting.html"><strong aria-hidden="true">5.10.</strong> Code formatting</a></li></ol></li><li class="chapter-item expanded "><a href="cpp.html"><strong aria-hidden="true">6.</strong> Generating Bindings to C++</a></li><li class="chapter-item expanded "><a href="objc.html" class="active"><strong aria-hidden="true">7.</strong> Generating Bindings to Objective-c</a></li><li class="chapter-item expanded "><a href="using-unions.html"><strong aria-hidden="true">8.</strong> Using Unions</a></li><li class="chapter-item expanded "><a href="using-bitfields.html"><strong aria-hidden="true">9.</strong> Using Bitfields</a></li><li class="chapter-item expanded "><a href="using-fam.html"><strong aria-hidden="true">10.</strong> Using Flexible Array Members</a></li><li class="chapter-item expanded "><a href="faq.html"><strong aria-hidden="true">11.</strong> FAQ</a></li></ol> |
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| <h1><a class="header" href="#generating-bindings-to-objective-c" id="generating-bindings-to-objective-c">Generating Bindings to Objective-C</a></h1> |
| <p><code>bindgen</code> does not (yet) have full objective-c support but it can generate bindings |
| for a lot of the apple frameworks without too much blocklisting.</p> |
| <p>In order to generate bindings, you will need <code>-x objective-c</code> as the clang |
| args. If you'd like to use <a href="https://crates.io/crates/block">block</a> you will need |
| <code>-fblocks</code> as a clang arg as well.</p> |
| <p>Depending on your setup, you may need <code>--generate-block</code> to generate the block |
| function aliases and <code>--block-extern-crate</code> to insert a <code>extern crate block</code> at |
| the beginning of the generated bindings. The same logic applies to the |
| <code>--objc-extern-crate</code> parameter.</p> |
| <p>The objective-c classes will be represented as a <code>struct Foo(id)</code> and a trait |
| <code>IFoo</code> where <code>Foo</code> is the objective-c class and <code>id</code> is an alias for <code>*mut objc::runtime::Object</code> (the pointer to the objective-c instance). The trait |
| <code>IFoo</code> is needed to allow for the generated inheritance.</p> |
| <p>Functions that use or return objective-c pointers of instance <code>Foo</code> will return |
| <code>Foo</code>. The reason this works is because <code>Foo</code> represented as <code>transparent</code>. |
| This will be helpful for a lot of objective-c frameworks however there are some |
| cases where functions return <code>instancetype</code> which is a type alias for <code>id</code> so |
| an occasional <code>foo.0</code> may be required. An example of this would in the UIKit |
| framework should you want to add a <code>UILabel</code> to a |
| <a href="https://developer.apple.com/documentation/uikit/uistackview/1616227-addarrangedsubview?language=objc">UIStackView</a> |
| you will need to convert the <code>UILabel</code> to a <code>UIView</code> via <code>UIView(label.0)</code>.</p> |
| <p>Each class (struct) has an <code>alloc</code> and a <code>dealloc</code> to match that of some of the alloc |
| methods found in <code>NSObject</code>.</p> |
| <p>In order to initialize a class <code>Foo</code>, you will have to do something like <code>let foo = Foo(Foo::alloc().initWithStuff())</code>.</p> |
| <p>To blocklist an Objective-C method, you should add the bindgen generated method |
| path (e.g. <code>IFoo::method</code> or <code>IFoo::class_method</code>) as a blocklist item.</p> |
| <h2><a class="header" href="#supported-features" id="supported-features">Supported Features</a></h2> |
| <ul> |
| <li>Inheritance matched to rust traits with prefixes of <code>I</code> which |
| stands for interface.</li> |
| <li>Protocols which match to rust traits with prefixes of <code>P</code> which |
| stands for Protocol.</li> |
| <li>Classes will generate <code>struct Foo(id)</code> where <code>Foo</code> is the class |
| name and <code>id</code> is a pointer to the objective-c Object.</li> |
| <li>Blocks</li> |
| </ul> |
| <h2><a class="header" href="#useful-notes" id="useful-notes">Useful Notes</a></h2> |
| <ul> |
| <li>If you're targeting <code>aarch64-apple-ios</code>, you'll need to have the clang arg |
| <code>--target=arm64-apple-ios</code> as mentioned |
| <a href="https://github.com/rust-lang/rust-bindgen/issues/1211#issuecomment-569804287">here</a>.</li> |
| <li>The generated bindings will almost certainly have some conflicts so you will |
| have to blocklist a few things. There are a few cases of the parameters being |
| poorly named in the objective-c headers. But if you're using anything with |
| Core Foundation, you'll find that <code>time.h</code> as has a variable called timezone that |
| conflicts with some of the things in <code>NSCalendar.h</code>.</li> |
| <li>Some small subset of the function headers in the apple frameworks go against |
| apple's guidelines for parameter names and duplicate the names in the header |
| which won't compile as mentioned |
| <a href="https://github.com/rust-lang/rust-bindgen/issues/1705">here</a>.</li> |
| <li>instancetype return methods does not return <code>Self</code> for you given class, it |
| returns a <code>mut * objc::runtime::Objc</code> which is aliased as <code>id</code>. This is because |
| objective-c's inheritance doesn't perfectly match that of rusts.</li> |
| <li>Depending on what you're trying <code>bindgen</code> against, you may end up including |
| all of Core Foundation and any other frameworks. This will result in a very |
| long compile time.</li> |
| </ul> |
| <h2><a class="header" href="#not-yet-supported" id="not-yet-supported">Not (yet) Supported</a></h2> |
| <ul> |
| <li>Nullability attributes which return <code>Option</code>s.</li> |
| <li>Probably many other things. Feel free to <a href="https://github.com/rust-lang/rust-bindgen/issues">open an issue</a>.</li> |
| </ul> |
| <h1><a class="header" href="#example-crates" id="example-crates">Example crate(s)</a></h1> |
| <ul> |
| <li><a href="https://github.com/simlay/uikit-sys">uikit-sys</a></li> |
| </ul> |
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