Subject: [Boost-commit] svn:boost r51200 - sandbox/thread_safe_signals/trunk/libs/signals2/doc/reference
From: fmhess_at_[hidden]
Date: 2009-02-11 10:32:58
Author: fmhess
Date: 2009-02-11 10:32:58 EST (Wed, 11 Feb 2009)
New Revision: 51200
URL: http://svn.boost.org/trac/boost/changeset/51200
Log:
Added a paragraph for the description of the optional_last_value
class on its reference page.
Text files modified:
sandbox/thread_safe_signals/trunk/libs/signals2/doc/reference/optional_last_value.xml | 21 ++++++++++++++++++++-
1 files changed, 20 insertions(+), 1 deletions(-)
Modified: sandbox/thread_safe_signals/trunk/libs/signals2/doc/reference/optional_last_value.xml
==============================================================================
--- sandbox/thread_safe_signals/trunk/libs/signals2/doc/reference/optional_last_value.xml (original)
+++ sandbox/thread_safe_signals/trunk/libs/signals2/doc/reference/optional_last_value.xml 2009-02-11 10:32:58 EST (Wed, 11 Feb 2009)
@@ -11,7 +11,17 @@
<purpose>Evaluate an <conceptname>InputIterator</conceptname> sequence and return
a boost::optional which contains the last value in the sequence, or an
- empty boost::optional if the sequence was empty.</purpose>
+ empty <classname>boost::optional</classname> if the sequence was empty.</purpose>
+ <description>
+ <para>
+ <code>optional_last_value</code> is the default Combiner template type for signals in the
+ Boost.Signals2 library. The advantage of <code>optional_last_value</code> over
+ <classname>last_value</classname> is that <code>optional_last_value</code>
+ can return an empty <classname>boost::optional</classname>. rather
+ than throwing an exception, when
+ its <code>InputIterator</code> sequence is empty.
+ </para>
+ </description>
<typedef name="result_type"><type><classname>boost::optional</classname><T></type></typedef>
@@ -48,6 +58,15 @@
</specialization>
<purpose>Evaluate an InputIterator sequence.</purpose>
+ <description>
+ <para>This specialization of <classname>optional_last_value</classname> is provided
+ to cope with the fact that there is no such thing as an
+ <code><classname>optional</classname><void></code>, which
+ <classname>optional_last_value</classname> would otherwise try to
+ use as its <code>result_type</code>. Therefore,
+ this specialization leaves the <code>result_type</code> unspecified.
+ </para>
+ </description>
<typedef name="result_type">
<type><emphasis>unspecified</emphasis></type>