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</style><table class="infobox vevent"><tbody><tr><th colspan="2" class="infobox-above summary">libsigc++</th></tr><tr style="display: none;"><td colspan="2" class="infobox-full-data"></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;"><a href="Software_release_life_cycle" title="Software release life cycle">Stable release</a></th><td class="infobox-data"><div style="margin:0px;">3.6.0
/ October 1, 2023<span style="display:none"> (<span class="bday dtstart published updated">2023-10-01</span>)</span><sup id="cite_ref-github-releases_1-0" class="reference"><a href="#cite_note-github-releases-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup></div></td></tr><tr style="display:none"><td colspan="2">
</td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;"><a href="Repository_(version_control)" title="Repository (version control)">Repository</a></th><td class="infobox-data"><style data-mw-deduplicate="TemplateStyles:r1126788409">
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</style><div class="plainlist"><ul><li><span class="url"><a rel="nofollow" class="external text" href="https://github.com/libsigcplusplus/libsigcplusplus">github<wbr>.com<wbr>/libsigcplusplus<wbr>/libsigcplusplus</a></span> </li></ul>
</div></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;">Written in</th><td class="infobox-data"><a href="C%2B%2B" title="C++">C++</a></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;"><a href="Software_categories#Categorization_approaches" title="Software categories">Type</a></th><td class="infobox-data"><a href="Library_(computing)" title="Library (computing)">library</a> or <a href="Software_framework" title="Software framework">framework</a></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;">Website</th><td class="infobox-data"><span class="url"><a rel="nofollow" class="external text" href="https://libsigcplusplus.github.io/libsigcplusplus/">libsigcplusplus<wbr>.github<wbr>.io<wbr>/libsigcplusplus<wbr>/</a></span> <span class="penicon autoconfirmed-show"></span></td></tr></tbody></table>
<p><br>
</p><p><b>libsigc++</b> is a <a href="C%2B%2B" title="C++">C++</a> library for <a href="Type_safety" title="Type safety">typesafe</a> <a href="Callback_(computer_science)" class="mw-redirect" title="Callback (computer science)">callbacks</a>.
</p><p>libsigc++ implements a callback system for use in abstract interfaces and general programming. libsigc++ is one of the earliest implementations of the <a href="Signals_and_slots" title="Signals and slots">signals and slots</a> concept implemented using C++ <a href="Template_metaprogramming" title="Template metaprogramming">template metaprogramming</a>. It was created as an alternative to the use of a meta compiler such as found in the signals and slots implementation in <a href="Qt_(framework)" class="mw-redirect" title="Qt (framework)">Qt</a>. libsigc++ originated as part of the <a href="Gtkmm" title="Gtkmm">gtkmm</a> project in 1997 and later was rewritten to be a standalone library. Each signal has a particular function profile which designates the number of arguments and argument type associated with the callback. Functions and methods are then wrapped using template calls to produce <a href="Function_objects" class="mw-redirect" title="Function objects">function objects</a> (functors) which can be bound to a signal. Each signal can be connected to multiple functors thus creating an <a href="Observer_pattern" title="Observer pattern">observer pattern</a> through which a message can be distributed to multiple anonymous listener objects. <a href="Reference_counting" title="Reference counting">Reference counting</a> based object lifespan tracking was used to disconnect the functors from signals as objects are deleted. The use of templates allowed for compile time typesafe verification of connections. The addition of this strict compile time checking required the addition of template typecasting adapters which convert the functor callback profile to match the required signal pattern.
</p><p>libsigc++ was a natural expansion of the <a href="C%2B%2B_standard_library" class="mw-redirect" title="C++ standard library">C++ standard library</a> functors to the tracking of objects necessary to implement the observer pattern. It inspired multiple C++ template based signal and slot implementations including the signal implementation used in the <a href="Boost_C%2B%2B_libraries" class="mw-redirect" title="Boost C++ libraries">boost C++ libraries</a>.
</p><p>libsigc++ is released as <a href="Free_software" title="Free software">free software</a> under the <a href="GNU_Lesser_General_Public_License" title="GNU Lesser General Public License">GNU Lesser General Public License</a> (LGPL).
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<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>
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</style><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://github.com/libsigcplusplus/libsigcplusplus/releases">"Releases - libsigcplusplus/libsigcplusplus"</a><span class="reference-accessdate">. Retrieved <span class="nowrap">7 February</span> 2025</span> – via <a href="GitHub" title="GitHub">GitHub</a>.</cite></span>
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<div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2></div>
<ul><li><span class="official-website"><span class="url"><a rel="nofollow" class="external text" href="https://libsigcplusplus.github.io/libsigcplusplus/">Official website</a></span></span> </li></ul>
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