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variant/doc/reference/get.xml
Eric Friedman bdf0cf5269 Started port of docs to BoostBook.
[SVN r18844]
2003-06-20 07:11:50 +00:00

96 lines
2.9 KiB
XML

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE header PUBLIC "-//Boost//DTD BoostBook XML V1.0//EN"
"http://www.boost.org/tools/boostbook/dtd/boostbook.dtd">
<header name="boost/variant/get.hpp">
<namespace name="boost">
<class name="bad_get">
<inherit access="public">
<classname>std::exception</classname>
</inherit>
<purpose>The exception thrown in the event of a failed
<code><functionname>get</functionname></code> of a
<code><classname>variant</classname></code> value.</purpose>
<method name="what" specifiers="virtual" cv="const">
<type>const char *</type>
</method>
</class>
<overloaded-function name="get">
<signature>
<template>
<template-type-parameter name="T"/>
</template>
<type>T &amp;</type>
<parameter name="operand">
<paramtype><classname>variant</classname>&lt;...&gt; &amp;</paramtype>
</parameter>
</signature>
<signature>
<template>
<template-type-parameter name="T"/>
</template>
<type>T &amp;</type>
<parameter name="operand">
<paramtype>const <classname>variant</classname>&lt;...&gt; &amp;</paramtype>
</parameter>
</signature>
<signature>
<template>
<template-type-parameter name="T"/>
</template>
<type>T *</type>
<parameter name="operand">
<paramtype><classname>variant</classname>&lt;...&gt; *</paramtype>
</parameter>
</signature>
<signature>
<template>
<template-type-parameter name="T"/>
</template>
<type>T *</type>
<parameter name="operand">
<paramtype>const <classname>variant</classname>&lt;...&gt; *</paramtype>
</parameter>
</signature>
<purpose><simpara>Retrieves a value of a specified type from a given
<code><classname>variant</classname></code>.</simpara>
</purpose>
<returns><simpara>If passed a pointer, it returns a similarly qualified
pointer to the value content if successful, otherwise null is returned.
If passed a reference, it returns a similarly qualified reference to the
value content if successful.</simpara>
</returns>
<throws><simpara>Overloads taking a
<code><classname>variant</classname></code> pointer do not
throw; the overloads taking a
<code><classname>variant</classname></code> reference throws
<code><classname>bad_get</classname></code> if
unsuccessful.</simpara>
</throws>
<rationale><simpara>While visitation via
<code><functionname>apply_visitor</functionname></code> is generally
prefered due to its greater safety, explicit retrieval via
<code>get</code> may be convenient in some circumstances.</simpara>
</rationale>
</overloaded-function>
</namespace>
</header>