[#7113C6D67A485E67D80B42BE0BE89DC4EA88734E]

<div id="7113C6D67A485E67D80B42BE0BE89DC4EA88734E">
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        <h2>Function <a href="#">url_view_base</a>::
persist</h2>
        <p><span>Return a shared, persistent copy of the url</span></p>


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        <h3>Synopsis</h3>
        <div>
            <code>
                            </code>
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        <pre class="source-code cpp">
            std::shared_ptr<url_view const>
persist() const;
        </pre>
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        <h3>Description</h3>
        <p><span>This function returns a read-only copy of</span> <span>the url, with shared lifetime. The returned</span>
<span>value owns (persists) the underlying string.</span>
<span>The algorithm used to create the value</span>
<span>minimizes the number of individual memory</span>
<span>allocations, making it more efficient than</span>
<span>when using direct standard library functions.</span></p>

<h3>Example</h3>
<code>
std::shared_ptr< url_view const > sp;
{
    std::string s( "http://example.com" );
    url_view u( s );                        // u references characters in s

    assert( u.data() == s.data() );         // same buffer

    sp = u.persist();

    assert( sp->data() != s.data() );       // different buffer
    assert( sp->buffer() == s);             // same contents

    // s is destroyed and thus u
    // becomes invalid, but sp remains valid.
}
</code>
<h3>Complexity</h3>
<p><span>Linear in `this->size()`.</span></p>

<h3>Exception Safety</h3>
<p><span>Calls to allocate may throw.</span></p>


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