mirror of https://gitee.com/bigwinds/arangodb
40 lines
1.7 KiB
XML
40 lines
1.7 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
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<!DOCTYPE section PUBLIC "-//Boost//DTD BoostBook XML V1.0//EN"
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"http://www.boost.org/tools/boostbook/dtd/boostbook.dtd">
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<section last-revision="$Date$">
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<title>Introduction</title>
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<note>
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<para><emphasis role="bold">Boost.Signals is no longer being actively maintained.</emphasis>
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Do not use Boost.Signals for new development (use
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<link linkend="signals2">Boost.Signals2</link>
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instead). If you have existing Boost.Signals-based code, it will
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continue to work, but consider moving to Boost.Signals2. There is
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<link linkend="signals2.porting">
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a porting guide</link> in the Signals2 documentation.</para>
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</note>
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<para>The Boost.Signals library is an implementation of a managed
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signals and slots system. Signals represent callbacks with multiple
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targets, and are also called publishers or events in similar
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systems. Signals are connected to some set of slots, which are
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callback receivers (also called event targets or subscribers), which
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are called when the signal is "emitted."</para>
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<para>Signals and slots are managed, in that signals and slots (or,
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more properly, objects that occur as part of the slots) track all
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connections and are capable of automatically disconnecting signal/slot
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connections when either is destroyed. This enables the user to make
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signal/slot connections without expending a great effort to manage the
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lifetimes of those connections with regard to the lifetimes of all
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objects involved.</para>
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<para>When signals are connected to multiple slots, there is a
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question regarding the relationship between the return values of the
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slots and the return value of the signals. Boost.Signals allows the
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user to specify the manner in which multiple return values are
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combined.</para>
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</section>
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