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<title>Issue 1397: Deprecate '98 binders</title>
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<p><em>This page is a snapshot from the LWG issues list, see the <a href="lwg-active.html">Library Active Issues List</a> for more information and the meaning of <a href="lwg-active.html#Resolved">Resolved</a> status.</em></p>
<h3 id="1397"><a href="lwg-defects.html#1397">1397</a>. Deprecate '98 binders</h3>
<p><b>Section:</b> 22.10 <a href="https://wg21.link/function.objects">[function.objects]</a> <b>Status:</b> <a href="lwg-active.html#Resolved">Resolved</a>
 <b>Submitter:</b> BSI <b>Opened:</b> 2010-08-25 <b>Last modified:</b> 2016-01-28</p>
<p><b>Priority: </b>Not Prioritized
</p>
<p><b>View all other</b> <a href="lwg-index.html#function.objects">issues</a> in [function.objects].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#Resolved">Resolved</a> status.</p>
<p><b>Discussion:</b></p>
<p><b>Addresses GB-95</b></p>
<p>
The adaptable function protocol supported by
<code>unary_function&#47;binary_function</code> has been superceded by
lambda expressions and <code>std::bind</code>. Despite the name, the
protocol is not very adaptable as it requires intrusive
support in the adaptable types, rather than offering an
external traits-like adaption mechanism. This protocol and
related support functions should be deprecated, and we
should not make onerous requirements for the
specification to support this protocol for callable types
introduced in this standard revision, including those
adopted from TR1. It is expected that high-quality
implementations will provide such support, but we should
not have to write robust standard specifications mixing this
restricted support with more general components such as
<code>function</code>, <code>bind</code> and <code>reference_wrapper</code>.
</p>

<p><i>[
Resolution proposed by ballot comment
]</i></p>

<p>
Move clauses 20.8.3, 20.8.9, 20.8.11 and 20.8.12
to Annex D.
<p/>
Remove the requirements to conditionally derive from
<code>unary&#47;binary_function</code> from <code>function</code>,
<code>reference_wrapper</code>, and the results of calling <code>mem_fn</code>
and <code>bind</code>.
</p>

<p><i>[
2010-10-24 Daniel adds:
]</i></p>


<blockquote><p>
Accepting <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2010/n3145.html">n3145</a> would solve this issue.
</p></blockquote>



<p id="res-1397"><b>Proposed resolution:</b></p><p>
Resolved by paper <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2010/n3198.htm">N3198</a>.
</p>




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