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<ul class="chapter"><li class="affix"><a href="introduction.html">Introduction</a></li><li><a href="notation.html"><strong>1.</strong> Notation</a></li><li><ul class="section"><li><a href="unicode-productions.html"><strong>1.1.</strong> Unicode productions</a></li><li><a href="string-table-productions.html"><strong>1.2.</strong> String table productions</a></li></ul></li><li><a href="lexical-structure.html"><strong>2.</strong> Lexical structure</a></li><li><ul class="section"><li><a href="input-format.html"><strong>2.1.</strong> Input format</a></li><li><a href="identifiers.html"><strong>2.2.</strong> Identifiers</a></li><li><a href="comments.html"><strong>2.3.</strong> Comments</a></li><li><a href="whitespace.html"><strong>2.4.</strong> Whitespace</a></li><li><a href="tokens.html"><strong>2.5.</strong> Tokens</a></li><li><a href="paths.html"><strong>2.6.</strong> Paths</a></li></ul></li><li><a href="macros.html"><strong>3.</strong> Macros</a></li><li><ul class="section"><li><a href="macros-by-example.html"><strong>3.1.</strong> Macros By Example</a></li><li><a href="procedural-macros.html"><strong>3.2.</strong> Procedural Macros</a></li></ul></li><li><a href="crates-and-source-files.html" class="active"><strong>4.</strong> Crates and source files</a></li><li><a href="items-and-attributes.html"><strong>5.</strong> Items and attributes</a></li><li><ul class="section"><li><a href="items.html"><strong>5.1.</strong> Items</a></li><li><a href="visibility-and-privacy.html"><strong>5.2.</strong> Visibility and Privacy</a></li><li><a href="attributes.html"><strong>5.3.</strong> Attributes</a></li></ul></li><li><a href="statements-and-expressions.html"><strong>6.</strong> Statements and expressions</a></li><li><ul class="section"><li><a href="statements.html"><strong>6.1.</strong> Statements</a></li><li><a href="expressions.html"><strong>6.2.</strong> Expressions</a></li></ul></li><li><a href="type-system.html"><strong>7.</strong> Type system</a></li><li><ul class="section"><li><a href="types.html"><strong>7.1.</strong> Types</a></li><li><a href="subtyping.html"><strong>7.2.</strong> Subtyping</a></li><li><a href="type-coercions.html"><strong>7.3.</strong> Type coercions</a></li></ul></li><li><a href="special-traits.html"><strong>8.</strong> Special traits</a></li><li><ul class="section"><li><a href="the-copy-trait.html"><strong>8.1.</strong> The Copy trait</a></li><li><a href="the-sized-trait.html"><strong>8.2.</strong> The Sized trait</a></li><li><a href="the-drop-trait.html"><strong>8.3.</strong> The Drop trait</a></li><li><a href="the-deref-trait.html"><strong>8.4.</strong> The Deref trait</a></li><li><a href="the-send-trait.html"><strong>8.5.</strong> The Send trait</a></li><li><a href="the-sync-trait.html"><strong>8.6.</strong> The Sync trait</a></li></ul></li><li><a href="memory-model.html"><strong>9.</strong> Memory model</a></li><li><ul class="section"><li><a href="memory-allocation-and-lifetime.html"><strong>9.1.</strong> Memory allocation and lifetime</a></li><li><a href="memory-ownership.html"><strong>9.2.</strong> Memory ownership</a></li><li><a href="variables.html"><strong>9.3.</strong> Variables</a></li></ul></li><li><a href="linkage.html"><strong>10.</strong> Linkage</a></li><li><a href="unsafety.html"><strong>11.</strong> Unsafety</a></li><li><ul class="section"><li><a href="unsafe-functions.html"><strong>11.1.</strong> Unsafe functions</a></li><li><a href="unsafe-blocks.html"><strong>11.2.</strong> Unsafe blocks</a></li><li><a href="behavior-considered-undefined.html"><strong>11.3.</strong> Behavior considered undefined</a></li><li><a href="behavior-not-considered-unsafe.html"><strong>11.4.</strong> Behavior not considered unsafe</a></li></ul></li><li><a href="influences.html">Appendix: Influences</a></li><li class="affix"><a href="undocumented.html">Appendix: As-yet-undocumented Features</a></li></ul>
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<h1 class="menu-title">The Rust Reference</h1>
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<a class="header" href="crates-and-source-files.html#crates-and-source-files" id="crates-and-source-files"><h1>Crates and source files</h1></a>
<p>Although Rust, like any other language, can be implemented by an interpreter as
well as a compiler, the only existing implementation is a compiler,
and the language has
always been designed to be compiled. For these reasons, this section assumes a
compiler.</p>
<p>Rust's semantics obey a <em>phase distinction</em> between compile-time and
run-time.<sup class="footnote-reference"><a href="crates-and-source-files.html#phase-distinction">1</a></sup> Semantic rules that have a <em>static
interpretation</em> govern the success or failure of compilation, while
semantic rules
that have a <em>dynamic interpretation</em> govern the behavior of the program at
run-time.</p>
<p>The compilation model centers on artifacts called <em>crates</em>. Each compilation
processes a single crate in source form, and if successful, produces a single
crate in binary form: either an executable or some sort of
library.<sup class="footnote-reference"><a href="crates-and-source-files.html#cratesourcefile">2</a></sup></p>
<p>A <em>crate</em> is a unit of compilation and linking, as well as versioning,
distribution and runtime loading. A crate contains a <em>tree</em> of nested
<a href="items.html#modules">module</a> scopes. The top level of this tree is a module that is
anonymous (from the point of view of paths within the module) and any item
within a crate has a canonical <a href="paths.html">module path</a> denoting its location
within the crate's module tree.</p>
<p>The Rust compiler is always invoked with a single source file as input, and
always produces a single output crate. The processing of that source file may
result in other source files being loaded as modules. Source files have the
extension <code>.rs</code>.</p>
<p>A Rust source file describes a module, the name and location of which —
in the module tree of the current crate — are defined from outside the
source file: either by an explicit <code>mod_item</code> in a referencing source file, or
by the name of the crate itself. Every source file is a module, but not every
module needs its own source file: <a href="items.html#modules">module definitions</a> can be nested
within one file.</p>
<p>Each source file contains a sequence of zero or more <code>item</code> definitions, and
may optionally begin with any number of <a href="items-and-attributes.html">attributes</a>
that apply to the containing module, most of which influence the behavior of
the compiler. The anonymous crate module can have additional attributes that
apply to the crate as a whole.</p>
<pre><pre class="playpen"><code class="language-rust no_run"># #![allow(unused_variables)]
#fn main() {
// Specify the crate name.
#![crate_name = "projx"]
// Specify the type of output artifact.
#![crate_type = "lib"]
// Turn on a warning.
// This can be done in any module, not just the anonymous crate module.
#![warn(non_camel_case_types)]
#}</code></pre></pre>
<p>A crate that contains a <code>main</code> function can be compiled to an executable. If a
<code>main</code> function is present, its return type must be <code>()</code>
("<a href="types.html#tuple-types">unit</a>") and it must take no arguments.</p>
<div class="footnote-definition" id="phase-distinction"><sup class="footnote-definition-label">1</sup>
<p>This distinction would also exist in an interpreter.
Static checks like syntactic analysis, type checking, and lints should
happen before the program is executed regardless of when it is executed.</p>
</div>
<div class="footnote-definition" id="cratesourcefile"><sup class="footnote-definition-label">2</sup>
<p>A crate is somewhat analogous to an <em>assembly</em> in the
ECMA-335 CLI model, a <em>library</em> in the SML/NJ Compilation Manager, a <em>unit</em>
in the Owens and Flatt module system, or a <em>configuration</em> in Mesa.</p>
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distrib
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Mageia
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6
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x86_64
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media
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core-updates
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by-pkgid
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878cdd00a13d17a73c6619a777ef5d74
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files
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2520
