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Diffstat (limited to 'libs/multi_index/doc/tutorial/basics.html')
| -rw-r--r-- | libs/multi_index/doc/tutorial/basics.html | 28 |
1 files changed, 18 insertions, 10 deletions
diff --git a/libs/multi_index/doc/tutorial/basics.html b/libs/multi_index/doc/tutorial/basics.html index f05d4218c..14ed98f17 100644 --- a/libs/multi_index/doc/tutorial/basics.html +++ b/libs/multi_index/doc/tutorial/basics.html @@ -474,6 +474,18 @@ means of user-defined <code>typedef</code>s: <span class=identifier>es</span><span class=special>.</span><span class=identifier>get</span><span class=special><</span><span class=number>1</span><span class=special>>().</span><span class=identifier>find</span><span class=special>(</span><span class=string>"Judy Smith"</span><span class=special>);</span> </pre></blockquote> +<p> +The iterators provided by every index are <i>constant</i>, that is, the elements they point to +cannot be mutated directly. This follows the interface of <code>std::set</code> for ordered +indices but might come as a surprise for other types such as sequenced indices, which are modeled after +<code>std::list</code>, where this limitation does not happen. This seemingly odd behavior +is imposed by the way <code>multi_index_container</code>s work; if elements were +allowed to be mutated indiscriminately, we could introduce inconsistencies +in the ordered indices of the <code>multi_index_container</code> without the container +being notified about it. Element modification is properly done by means of +<a href="#ord_updating">update operations</a> on any index. +</p> + <h2> <a name="index_types">Index types</a> </h2> @@ -1060,9 +1072,9 @@ same way as <code>std::list</code> permits. The interface of sequenced indices is thus designed upon that of <code>std::list</code>; nearly every operation provided in the standard container is replicated here, occasionally with changes in the syntax and/or semantics to cope with the constraints imposed by -Boost.MultiIndex. In particular, there is an important limitation of sequenced -indices with respect to <code>std::list</code>s, namely that elements of an -<code>multi_index_container</code> are not mutable through an iterator: +Boost.MultiIndex. An important difference, commented <a href="#iterator_access">above</a>, +is the fact that the values pointed to by sequenced index iterators are treated +as <i>constant</i>: </p> <blockquote><pre> @@ -1076,11 +1088,7 @@ indices with respect to <code>std::list</code>s, namely that elements of an </pre></blockquote> <p> -That is, iterators of a sequenced index (of all types of indices, actually) -point to constant elements. This limitation might come as a surprise, but -it is imposed by the way <code>multi_index_container</code>s work; if elements were -allowed to be changed in this manner, we could introduce inconsistencies -in other ordered indices of the <code>multi_index_container</code>. Element modification +As with any other type of index, element modification can nevertheless be done by means of <a href="#seq_updating">update operations</a>. </p> @@ -1240,9 +1248,9 @@ Index types <br> -<p>Revised November 7th 2008</p> +<p>Revised November 11th 2014</p> -<p>© Copyright 2003-2008 Joaquín M López Muñoz. +<p>© Copyright 2003-2014 Joaquín M López Muñoz. Distributed under the Boost Software License, Version 1.0. (See accompanying file <a href="../../../../LICENSE_1_0.txt"> LICENSE_1_0.txt</a> or copy at <a href="http://www.boost.org/LICENSE_1_0.txt"> |