| <?xml version="1.0" encoding="utf-8"?> |
| <!DOCTYPE section PUBLIC "-//Boost//DTD BoostBook XML V1.0//EN" |
| "http://www.boost.org/tools/boostbook/dtd/boostbook.dtd"> |
| <section last-revision="$Date: 2007-11-25 13:38:02 -0500 (Sun, 25 Nov 2007) $"> |
| <title>Introduction</title> |
| |
| <para>The Boost.Signals library is an implementation of a managed |
| signals and slots system. Signals represent callbacks with multiple |
| targets, and are also called publishers or events in similar |
| systems. Signals are connected to some set of slots, which are |
| callback receivers (also called event targets or subscribers), which |
| are called when the signal is "emitted."</para> |
| |
| <para>Signals and slots are managed, in that signals and slots (or, |
| more properly, objects that occur as part of the slots) track all |
| connections and are capable of automatically disconnecting signal/slot |
| connections when either is destroyed. This enables the user to make |
| signal/slot connections without expending a great effort to manage the |
| lifetimes of those connections with regard to the lifetimes of all |
| objects involved.</para> |
| |
| <para>When signals are connected to multiple slots, there is a |
| question regarding the relationship between the return values of the |
| slots and the return value of the signals. Boost.Signals allows the |
| user to specify the manner in which multiple return values are |
| combined.</para> |
| |
| </section> |
