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<ol class="chapter"><li class="chapter-item expanded "><a href="../../intro.html"><strong aria-hidden="true">1.</strong> Introduction</a></li><li class="chapter-item expanded "><a href="../../idioms/index.html"><strong aria-hidden="true">2.</strong> Idioms</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../idioms/coercion-arguments.html"><strong aria-hidden="true">2.1.</strong> Use borrowed types for arguments</a></li><li class="chapter-item expanded "><a href="../../idioms/concat-format.html"><strong aria-hidden="true">2.2.</strong> Concatenating Strings with format!</a></li><li class="chapter-item expanded "><a href="../../idioms/ctor.html"><strong aria-hidden="true">2.3.</strong> Constructor</a></li><li class="chapter-item expanded "><a href="../../idioms/default.html"><strong aria-hidden="true">2.4.</strong> The Default Trait</a></li><li class="chapter-item expanded "><a href="../../idioms/deref.html"><strong aria-hidden="true">2.5.</strong> Collections Are Smart Pointers</a></li><li class="chapter-item expanded "><a href="../../idioms/dtor-finally.html"><strong aria-hidden="true">2.6.</strong> Finalisation in Destructors</a></li><li class="chapter-item expanded "><a href="../../idioms/mem-replace.html"><strong aria-hidden="true">2.7.</strong> mem::{take(), replace()}</a></li><li class="chapter-item expanded "><a href="../../idioms/on-stack-dyn-dispatch.html"><strong aria-hidden="true">2.8.</strong> On-Stack Dynamic Dispatch</a></li><li class="chapter-item expanded "><a href="../../idioms/ffi/intro.html" class="active"><strong aria-hidden="true">2.9.</strong> Foreign function interface (FFI)</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../idioms/ffi/errors.html"><strong aria-hidden="true">2.9.1.</strong> Idiomatic Errors</a></li><li class="chapter-item expanded "><a href="../../idioms/ffi/accepting-strings.html"><strong aria-hidden="true">2.9.2.</strong> Accepting Strings</a></li><li class="chapter-item expanded "><a href="../../idioms/ffi/passing-strings.html"><strong aria-hidden="true">2.9.3.</strong> Passing Strings</a></li></ol></li><li class="chapter-item expanded "><a href="../../idioms/option-iter.html"><strong aria-hidden="true">2.10.</strong> Iterating over an Option</a></li><li class="chapter-item expanded "><a href="../../idioms/pass-var-to-closure.html"><strong aria-hidden="true">2.11.</strong> Pass Variables to Closure</a></li><li class="chapter-item expanded "><a href="../../idioms/priv-extend.html"><strong aria-hidden="true">2.12.</strong> Privacy For Extensibility</a></li><li class="chapter-item expanded "><a href="../../idioms/rustdoc-init.html"><strong aria-hidden="true">2.13.</strong> Easy doc initialization</a></li><li class="chapter-item expanded "><a href="../../idioms/temporary-mutability.html"><strong aria-hidden="true">2.14.</strong> Temporary mutability</a></li></ol></li><li class="chapter-item expanded "><a href="../../patterns/index.html"><strong aria-hidden="true">3.</strong> Design Patterns</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../patterns/behavioural/intro.html"><strong aria-hidden="true">3.1.</strong> Behavioural</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../patterns/behavioural/command.html"><strong aria-hidden="true">3.1.1.</strong> Command</a></li><li class="chapter-item expanded "><a href="../../patterns/behavioural/interpreter.html"><strong aria-hidden="true">3.1.2.</strong> Interpreter</a></li><li class="chapter-item expanded "><a href="../../patterns/behavioural/newtype.html"><strong aria-hidden="true">3.1.3.</strong> Newtype</a></li><li class="chapter-item expanded "><a href="../../patterns/behavioural/RAII.html"><strong aria-hidden="true">3.1.4.</strong> RAII Guards</a></li><li class="chapter-item expanded "><a href="../../patterns/behavioural/strategy.html"><strong aria-hidden="true">3.1.5.</strong> Strategy</a></li><li class="chapter-item expanded "><a href="../../patterns/behavioural/visitor.html"><strong aria-hidden="true">3.1.6.</strong> Visitor</a></li></ol></li><li class="chapter-item expanded "><a href="../../patterns/creational/intro.html"><strong aria-hidden="true">3.2.</strong> Creational</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../patterns/creational/builder.html"><strong aria-hidden="true">3.2.1.</strong> Builder</a></li><li class="chapter-item expanded "><a href="../../patterns/creational/fold.html"><strong aria-hidden="true">3.2.2.</strong> Fold</a></li></ol></li><li class="chapter-item expanded "><a href="../../patterns/structural/intro.html"><strong aria-hidden="true">3.3.</strong> Structural</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../patterns/structural/compose-structs.html"><strong aria-hidden="true">3.3.1.</strong> Compose Structs</a></li><li class="chapter-item expanded "><a href="../../patterns/structural/small-crates.html"><strong aria-hidden="true">3.3.2.</strong> Prefer Small Crates</a></li><li class="chapter-item expanded "><a href="../../patterns/structural/unsafe-mods.html"><strong aria-hidden="true">3.3.3.</strong> Contain unsafety in small modules</a></li></ol></li><li class="chapter-item expanded "><a href="../../patterns/ffi/intro.html"><strong aria-hidden="true">3.4.</strong> Foreign function interface (FFI)</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../patterns/ffi/export.html"><strong aria-hidden="true">3.4.1.</strong> Object-Based APIs</a></li><li class="chapter-item expanded "><a href="../../patterns/ffi/wrappers.html"><strong aria-hidden="true">3.4.2.</strong> Type Consolidation into Wrappers</a></li></ol></li></ol></li><li class="chapter-item expanded "><a href="../../anti_patterns/index.html"><strong aria-hidden="true">4.</strong> Anti-patterns</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../anti_patterns/borrow_clone.html"><strong aria-hidden="true">4.1.</strong> Clone to satisfy the borrow checker</a></li><li class="chapter-item expanded "><a href="../../anti_patterns/deny-warnings.html"><strong aria-hidden="true">4.2.</strong> #[deny(warnings)]</a></li><li class="chapter-item expanded "><a href="../../anti_patterns/deref.html"><strong aria-hidden="true">4.3.</strong> Deref Polymorphism</a></li></ol></li><li class="chapter-item expanded "><a href="../../functional/index.html"><strong aria-hidden="true">5.</strong> Functional Programming</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../functional/paradigms.html"><strong aria-hidden="true">5.1.</strong> Programming paradigms</a></li></ol></li><li class="chapter-item expanded "><a href="../../additional_resources/index.html"><strong aria-hidden="true">6.</strong> Additional Resources</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../../additional_resources/design-principles.html"><strong aria-hidden="true">6.1.</strong> Design principles</a></li></ol></li></ol>
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<h1 id="ffi-idioms"><a class="header" href="#ffi-idioms">FFI Idioms</a></h1>
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<p>Writing FFI code is an entire course in itself.
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However, there are several idioms here that can act as pointers, and avoid
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traps for inexperienced users of <code>unsafe</code> Rust.</p>
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<p>This section contains idioms that may be useful when doing FFI.</p>
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