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<section id='main' class="content macro">
<h1 class='fqn'><span class='in-band'><a href='index.html'>bitflags</a>::<wbr><a class='macro' href=''>bitflags!</a></span><span class='out-of-band'><span id='render-detail'>
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</span><a id='src-4' class='srclink' href='../src/bitflags/lib.rs.html#127-288' title='goto source code'>[src]</a></span></h1>
<pre class='rust macro'>
<span class='macro'>macro_rules</span><span class='macro'>!</span> <span class='ident'>bitflags</span> {
($(<span class='attribute'>#[<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>attr</span>:<span class='ident'>meta</span>]</span>)<span class='op'>*</span> <span class='ident'>flags</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>:<span class='ident'>ident</span>: <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>T</span>:<span class='ident'>ty</span> {
$($(<span class='attribute'>#[<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>Flag_attr</span>:<span class='ident'>meta</span>]</span>)<span class='op'>*</span> <span class='kw'>const</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>Flag</span>:<span class='ident'>ident</span> <span class='op'>=</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>value</span>:<span class='ident'>expr</span>),<span class='op'>+</span>
}) <span class='op'>=></span> {
<span class='attribute'>#[<span class='ident'>derive</span>(<span class='ident'>Copy</span>, <span class='ident'>PartialEq</span>, <span class='ident'>Eq</span>, <span class='ident'>Clone</span>, <span class='ident'>PartialOrd</span>, <span class='ident'>Ord</span>, <span class='ident'>Hash</span>)]</span>
$(<span class='attribute'>#[<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>attr</span>]</span>)<span class='op'>*</span>
<span class='kw'>pub</span> <span class='kw'>struct</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> {
<span class='ident'>bits</span>: <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>T</span>,
}
$($(<span class='attribute'>#[<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>Flag_attr</span>]</span>)<span class='op'>*</span> <span class='kw'>pub</span> <span class='kw'>const</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>Flag</span>: <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> <span class='op'>=</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> { <span class='ident'>bits</span>: <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>value</span> };)<span class='op'>+</span>
<span class='kw'>impl</span> ::<span class='ident'>std</span>::<span class='ident'>fmt</span>::<span class='ident'>Debug</span> <span class='kw'>for</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> {
<span class='kw'>fn</span> <span class='ident'>fmt</span>(<span class='kw-2'>&</span><span class='self'>self</span>, <span class='ident'>f</span>: <span class='kw-2'>&</span><span class='kw-2'>mut</span> ::<span class='ident'>std</span>::<span class='ident'>fmt</span>::<span class='ident'>Formatter</span>) <span class='op'>-></span> ::<span class='ident'>std</span>::<span class='ident'>fmt</span>::<span class='prelude-ty'>Result</span> {
<span class='kw'>let</span> <span class='ident'>out</span> <span class='op'>=</span> <span class='macro'>format</span><span class='macro'>!</span>(<span class='string'>"{} {{ bits: {:#b} }}"</span>,
<span class='macro'>stringify</span><span class='macro'>!</span>(<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>),
<span class='self'>self</span>.<span class='ident'>bits</span>);
<span class='ident'>f</span>.<span class='ident'>write_str</span>(<span class='kw-2'>&</span><span class='ident'>out</span>[..])
}
}
<span class='kw'>impl</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> {
<span class='doccomment'>/// Returns an empty set of flags.</span>
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>pub</span> <span class='kw'>fn</span> <span class='ident'>empty</span>() <span class='op'>-></span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> {
<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> { <span class='ident'>bits</span>: <span class='number'>0</span> }
}
<span class='doccomment'>/// Returns the set containing all flags.</span>
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>pub</span> <span class='kw'>fn</span> <span class='ident'>all</span>() <span class='op'>-></span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> {
<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> { <span class='ident'>bits</span>: $(<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>value</span>)<span class='op'>|</span><span class='op'>+</span> }
}
<span class='doccomment'>/// Returns the raw value of the flags currently stored.</span>
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>pub</span> <span class='kw'>fn</span> <span class='ident'>bits</span>(<span class='kw-2'>&</span><span class='self'>self</span>) <span class='op'>-></span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>T</span> {
<span class='self'>self</span>.<span class='ident'>bits</span>
}
<span class='doccomment'>/// Convert from underlying bit representation, unless that</span>
<span class='doccomment'>/// representation contains bits that do not correspond to a flag.</span>
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>pub</span> <span class='kw'>fn</span> <span class='ident'>from_bits</span>(<span class='ident'>bits</span>: <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>T</span>) <span class='op'>-></span> ::<span class='ident'>std</span>::<span class='ident'>option</span>::<span class='prelude-ty'>Option</span><span class='op'><</span><span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span><span class='op'>></span> {
<span class='kw'>if</span> (<span class='ident'>bits</span> <span class='kw-2'>&</span> <span class='op'>!</span><span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>::<span class='ident'>all</span>().<span class='ident'>bits</span>()) <span class='op'>!=</span> <span class='number'>0</span> {
::<span class='ident'>std</span>::<span class='ident'>option</span>::<span class='prelude-ty'>Option</span>::<span class='prelude-val'>None</span>
} <span class='kw'>else</span> {
::<span class='ident'>std</span>::<span class='ident'>option</span>::<span class='prelude-ty'>Option</span>::<span class='prelude-val'>Some</span>(<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> { <span class='ident'>bits</span>: <span class='ident'>bits</span> })
}
}
<span class='doccomment'>/// Convert from underlying bit representation, dropping any bits</span>
<span class='doccomment'>/// that do not correspond to flags.</span>
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>pub</span> <span class='kw'>fn</span> <span class='ident'>from_bits_truncate</span>(<span class='ident'>bits</span>: <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>T</span>) <span class='op'>-></span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> {
<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> { <span class='ident'>bits</span>: <span class='ident'>bits</span> } <span class='kw-2'>&</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>::<span class='ident'>all</span>()
}
<span class='doccomment'>/// Returns `true` if no flags are currently stored.</span>
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>pub</span> <span class='kw'>fn</span> <span class='ident'>is_empty</span>(<span class='kw-2'>&</span><span class='self'>self</span>) <span class='op'>-></span> <span class='ident'>bool</span> {
<span class='op'>*</span><span class='self'>self</span> <span class='op'>==</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>::<span class='ident'>empty</span>()
}
<span class='doccomment'>/// Returns `true` if all flags are currently set.</span>
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>pub</span> <span class='kw'>fn</span> <span class='ident'>is_all</span>(<span class='kw-2'>&</span><span class='self'>self</span>) <span class='op'>-></span> <span class='ident'>bool</span> {
<span class='op'>*</span><span class='self'>self</span> <span class='op'>==</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>::<span class='ident'>all</span>()
}
<span class='doccomment'>/// Returns `true` if there are flags common to both `self` and `other`.</span>
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>pub</span> <span class='kw'>fn</span> <span class='ident'>intersects</span>(<span class='kw-2'>&</span><span class='self'>self</span>, <span class='ident'>other</span>: <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>) <span class='op'>-></span> <span class='ident'>bool</span> {
<span class='op'>!</span>(<span class='op'>*</span><span class='self'>self</span> <span class='kw-2'>&</span> <span class='ident'>other</span>).<span class='ident'>is_empty</span>()
}
<span class='doccomment'>/// Returns `true` all of the flags in `other` are contained within `self`.</span>
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>pub</span> <span class='kw'>fn</span> <span class='ident'>contains</span>(<span class='kw-2'>&</span><span class='self'>self</span>, <span class='ident'>other</span>: <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>) <span class='op'>-></span> <span class='ident'>bool</span> {
(<span class='op'>*</span><span class='self'>self</span> <span class='kw-2'>&</span> <span class='ident'>other</span>) <span class='op'>==</span> <span class='ident'>other</span>
}
<span class='doccomment'>/// Inserts the specified flags in-place.</span>
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>pub</span> <span class='kw'>fn</span> <span class='ident'>insert</span>(<span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='self'>self</span>, <span class='ident'>other</span>: <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>) {
<span class='self'>self</span>.<span class='ident'>bits</span> <span class='op'>|=</span> <span class='ident'>other</span>.<span class='ident'>bits</span>;
}
<span class='doccomment'>/// Removes the specified flags in-place.</span>
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>pub</span> <span class='kw'>fn</span> <span class='ident'>remove</span>(<span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='self'>self</span>, <span class='ident'>other</span>: <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>) {
<span class='self'>self</span>.<span class='ident'>bits</span> <span class='op'>&=</span> <span class='op'>!</span><span class='ident'>other</span>.<span class='ident'>bits</span>;
}
<span class='doccomment'>/// Toggles the specified flags in-place.</span>
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>pub</span> <span class='kw'>fn</span> <span class='ident'>toggle</span>(<span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='self'>self</span>, <span class='ident'>other</span>: <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>) {
<span class='self'>self</span>.<span class='ident'>bits</span> <span class='op'>^=</span> <span class='ident'>other</span>.<span class='ident'>bits</span>;
}
}
<span class='kw'>impl</span> ::<span class='ident'>std</span>::<span class='ident'>ops</span>::<span class='ident'>BitOr</span> <span class='kw'>for</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> {
<span class='kw'>type</span> <span class='ident'>Output</span> <span class='op'>=</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>;
<span class='doccomment'>/// Returns the union of the two sets of flags.</span>
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>bitor</span>(<span class='self'>self</span>, <span class='ident'>other</span>: <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>) <span class='op'>-></span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> {
<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> { <span class='ident'>bits</span>: <span class='self'>self</span>.<span class='ident'>bits</span> <span class='op'>|</span> <span class='ident'>other</span>.<span class='ident'>bits</span> }
}
}
<span class='kw'>impl</span> ::<span class='ident'>std</span>::<span class='ident'>ops</span>::<span class='ident'>BitXor</span> <span class='kw'>for</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> {
<span class='kw'>type</span> <span class='ident'>Output</span> <span class='op'>=</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>;
<span class='doccomment'>/// Returns the left flags, but with all the right flags toggled.</span>
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>bitxor</span>(<span class='self'>self</span>, <span class='ident'>other</span>: <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>) <span class='op'>-></span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> {
<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> { <span class='ident'>bits</span>: <span class='self'>self</span>.<span class='ident'>bits</span> <span class='op'>^</span> <span class='ident'>other</span>.<span class='ident'>bits</span> }
}
}
<span class='kw'>impl</span> ::<span class='ident'>std</span>::<span class='ident'>ops</span>::<span class='ident'>BitAnd</span> <span class='kw'>for</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> {
<span class='kw'>type</span> <span class='ident'>Output</span> <span class='op'>=</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>;
<span class='doccomment'>/// Returns the intersection between the two sets of flags.</span>
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>bitand</span>(<span class='self'>self</span>, <span class='ident'>other</span>: <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>) <span class='op'>-></span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> {
<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> { <span class='ident'>bits</span>: <span class='self'>self</span>.<span class='ident'>bits</span> <span class='kw-2'>&</span> <span class='ident'>other</span>.<span class='ident'>bits</span> }
}
}
<span class='kw'>impl</span> ::<span class='ident'>std</span>::<span class='ident'>ops</span>::<span class='ident'>Sub</span> <span class='kw'>for</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> {
<span class='kw'>type</span> <span class='ident'>Output</span> <span class='op'>=</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>;
<span class='doccomment'>/// Returns the set difference of the two sets of flags.</span>
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>sub</span>(<span class='self'>self</span>, <span class='ident'>other</span>: <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>) <span class='op'>-></span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> {
<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> { <span class='ident'>bits</span>: <span class='self'>self</span>.<span class='ident'>bits</span> <span class='kw-2'>&</span> <span class='op'>!</span><span class='ident'>other</span>.<span class='ident'>bits</span> }
}
}
<span class='kw'>impl</span> ::<span class='ident'>std</span>::<span class='ident'>ops</span>::<span class='ident'>Not</span> <span class='kw'>for</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> {
<span class='kw'>type</span> <span class='ident'>Output</span> <span class='op'>=</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>;
<span class='doccomment'>/// Returns the complement of this set of flags.</span>
<span class='attribute'>#[<span class='ident'>inline</span>]</span>
<span class='kw'>fn</span> <span class='ident'>not</span>(<span class='self'>self</span>) <span class='op'>-></span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> {
<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span> { <span class='ident'>bits</span>: <span class='op'>!</span><span class='self'>self</span>.<span class='ident'>bits</span> } <span class='kw-2'>&</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>::<span class='ident'>all</span>()
}
}
};
($(<span class='attribute'>#[<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>attr</span>:<span class='ident'>meta</span>]</span>)<span class='op'>*</span> <span class='ident'>flags</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>:<span class='ident'>ident</span>: <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>T</span>:<span class='ident'>ty</span> {
$($(<span class='attribute'>#[<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>Flag_attr</span>:<span class='ident'>meta</span>]</span>)<span class='op'>*</span> <span class='kw'>const</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>Flag</span>:<span class='ident'>ident</span> <span class='op'>=</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>value</span>:<span class='ident'>expr</span>),<span class='op'>+</span>,
}) <span class='op'>=></span> {
<span class='macro'>bitflags</span><span class='macro'>!</span> {
$(<span class='attribute'>#[<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>attr</span>]</span>)<span class='op'>*</span>
<span class='ident'>flags</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>BitFlags</span>: <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>T</span> {
$($(<span class='attribute'>#[<span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>Flag_attr</span>]</span>)<span class='op'>*</span> <span class='kw'>const</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>Flag</span> <span class='op'>=</span> <span class='macro-nonterminal'>$</span><span class='macro-nonterminal'>value</span>),<span class='op'>+</span>
}
}
};
}
</pre>
<div class='docblock'><p>The <code>bitflags!</code> macro generates a <code>struct</code> that holds a set of C-style
bitmask flags. It is useful for creating typesafe wrappers for C APIs.</p>
<p>The flags should only be defined for integer types, otherwise unexpected
type errors may occur at compile time.</p>
<h1 id="example" class='section-header'><a
href="#example">Example</a></h1><pre class='rust rust-example-rendered'>
<span class='attribute'>#[<span class='ident'>macro_use</span>]</span>
<span class='kw'>extern</span> <span class='kw'>crate</span> <span class='ident'>bitflags</span>;
<span class='macro'>bitflags</span><span class='macro'>!</span> {
<span class='ident'>flags</span> <span class='ident'>Flags</span>: <span class='ident'>u32</span> {
<span class='kw'>const</span> <span class='ident'>FLAG_A</span> <span class='op'>=</span> <span class='number'>0b00000001</span>,
<span class='kw'>const</span> <span class='ident'>FLAG_B</span> <span class='op'>=</span> <span class='number'>0b00000010</span>,
<span class='kw'>const</span> <span class='ident'>FLAG_C</span> <span class='op'>=</span> <span class='number'>0b00000100</span>,
<span class='kw'>const</span> <span class='ident'>FLAG_ABC</span> <span class='op'>=</span> <span class='ident'>FLAG_A</span>.<span class='ident'>bits</span>
<span class='op'>|</span> <span class='ident'>FLAG_B</span>.<span class='ident'>bits</span>
<span class='op'>|</span> <span class='ident'>FLAG_C</span>.<span class='ident'>bits</span>,
}
}
<span class='kw'>fn</span> <span class='ident'>main</span>() {
<span class='kw'>let</span> <span class='ident'>e1</span> <span class='op'>=</span> <span class='ident'>FLAG_A</span> <span class='op'>|</span> <span class='ident'>FLAG_C</span>;
<span class='kw'>let</span> <span class='ident'>e2</span> <span class='op'>=</span> <span class='ident'>FLAG_B</span> <span class='op'>|</span> <span class='ident'>FLAG_C</span>;
<span class='macro'>assert</span><span class='macro'>!</span>((<span class='ident'>e1</span> <span class='op'>|</span> <span class='ident'>e2</span>) <span class='op'>==</span> <span class='ident'>FLAG_ABC</span>); <span class='comment'>// union</span>
<span class='macro'>assert</span><span class='macro'>!</span>((<span class='ident'>e1</span> <span class='kw-2'>&</span> <span class='ident'>e2</span>) <span class='op'>==</span> <span class='ident'>FLAG_C</span>); <span class='comment'>// intersection</span>
<span class='macro'>assert</span><span class='macro'>!</span>((<span class='ident'>e1</span> <span class='op'>-</span> <span class='ident'>e2</span>) <span class='op'>==</span> <span class='ident'>FLAG_A</span>); <span class='comment'>// set difference</span>
<span class='macro'>assert</span><span class='macro'>!</span>(<span class='op'>!</span><span class='ident'>e2</span> <span class='op'>==</span> <span class='ident'>FLAG_A</span>); <span class='comment'>// set complement</span>
}
</pre>
<p>The generated <code>struct</code>s can also be extended with type and trait
implementations:</p>
<pre class='rust rust-example-rendered'>
<span class='attribute'>#[<span class='ident'>macro_use</span>]</span>
<span class='kw'>extern</span> <span class='kw'>crate</span> <span class='ident'>bitflags</span>;
<span class='kw'>use</span> <span class='ident'>std</span>::<span class='ident'>fmt</span>;
<span class='macro'>bitflags</span><span class='macro'>!</span> {
<span class='ident'>flags</span> <span class='ident'>Flags</span>: <span class='ident'>u32</span> {
<span class='kw'>const</span> <span class='ident'>FLAG_A</span> <span class='op'>=</span> <span class='number'>0b00000001</span>,
<span class='kw'>const</span> <span class='ident'>FLAG_B</span> <span class='op'>=</span> <span class='number'>0b00000010</span>,
}
}
<span class='kw'>impl</span> <span class='ident'>Flags</span> {
<span class='kw'>pub</span> <span class='kw'>fn</span> <span class='ident'>clear</span>(<span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='self'>self</span>) {
<span class='self'>self</span>.<span class='ident'>bits</span> <span class='op'>=</span> <span class='number'>0</span>; <span class='comment'>// The `bits` field can be accessed from within the</span>
<span class='comment'>// same module where the `bitflags!` macro was invoked.</span>
}
}
<span class='kw'>impl</span> <span class='ident'>fmt</span>::<span class='ident'>Display</span> <span class='kw'>for</span> <span class='ident'>Flags</span> {
<span class='kw'>fn</span> <span class='ident'>fmt</span>(<span class='kw-2'>&</span><span class='self'>self</span>, <span class='ident'>f</span>: <span class='kw-2'>&</span><span class='kw-2'>mut</span> <span class='ident'>fmt</span>::<span class='ident'>Formatter</span>) <span class='op'>-></span> <span class='ident'>fmt</span>::<span class='prelude-ty'>Result</span> {
<span class='macro'>write</span><span class='macro'>!</span>(<span class='ident'>f</span>, <span class='string'>"hi!"</span>)
}
}
<span class='kw'>fn</span> <span class='ident'>main</span>() {
<span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>flags</span> <span class='op'>=</span> <span class='ident'>FLAG_A</span> <span class='op'>|</span> <span class='ident'>FLAG_B</span>;
<span class='ident'>flags</span>.<span class='ident'>clear</span>();
<span class='macro'>assert</span><span class='macro'>!</span>(<span class='ident'>flags</span>.<span class='ident'>is_empty</span>());
<span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='macro'>format</span><span class='macro'>!</span>(<span class='string'>"{}"</span>, <span class='ident'>flags</span>), <span class='string'>"hi!"</span>);
<span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='macro'>format</span><span class='macro'>!</span>(<span class='string'>"{:?}"</span>, <span class='ident'>FLAG_A</span> <span class='op'>|</span> <span class='ident'>FLAG_B</span>), <span class='string'>"Flags { bits: 0b11 }"</span>);
<span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='macro'>format</span><span class='macro'>!</span>(<span class='string'>"{:?}"</span>, <span class='ident'>FLAG_B</span>), <span class='string'>"Flags { bits: 0b10 }"</span>);
}
</pre>
<h1 id="attributes" class='section-header'><a
href="#attributes">Attributes</a></h1>
<p>Attributes can be attached to the generated <code>struct</code> by placing them
before the <code>flags</code> keyword.</p>
<h1 id="derived-traits" class='section-header'><a
href="#derived-traits">Derived traits</a></h1>
<p>The <code>PartialEq</code> and <code>Clone</code> traits are automatically derived for the
<code>struct</code> using the <code>deriving</code> attribute. Additional traits can be derived by
providing an explicit <code>deriving</code> attribute on <code>flags</code>. The <code>Debug</code> trait is
also implemented by displaying the bits value of the internal struct.</p>
<h1 id="operators" class='section-header'><a
href="#operators">Operators</a></h1>
<p>The following operator traits are implemented for the generated <code>struct</code>:</p>
<ul>
<li><code>BitOr</code>: union</li>
<li><code>BitAnd</code>: intersection</li>
<li><code>BitXor</code>: toggle</li>
<li><code>Sub</code>: set difference</li>
<li><code>Not</code>: set complement</li>
</ul>
<h1 id="methods" class='section-header'><a
href="#methods">Methods</a></h1>
<p>The following methods are defined for the generated <code>struct</code>:</p>
<ul>
<li><code>empty</code>: an empty set of flags</li>
<li><code>all</code>: the set of all flags</li>
<li><code>bits</code>: the raw value of the flags currently stored</li>
<li><code>from_bits</code>: convert from underlying bit representation, unless that
representation contains bits that do not correspond to a flag</li>
<li><code>from_bits_truncate</code>: convert from underlying bit representation, dropping
any bits that do not correspond to flags</li>
<li><code>is_empty</code>: <code>true</code> if no flags are currently stored</li>
<li><code>is_all</code>: <code>true</code> if all flags are currently set</li>
<li><code>intersects</code>: <code>true</code> if there are flags common to both <code>self</code> and <code>other</code></li>
<li><code>contains</code>: <code>true</code> all of the flags in <code>other</code> are contained within <code>self</code></li>
<li><code>insert</code>: inserts the specified flags in-place</li>
<li><code>remove</code>: removes the specified flags in-place</li>
<li><code>toggle</code>: the specified flags will be inserted if not present, and removed
if they are.</li>
</ul>
</div></section>
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