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&#160;<span id="projectnumber">1.4.0</span>
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<div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno"> 1</span>&#160;![cynny-logo](https://web.cynny.com/live/static/favicon/favicon-16.png) **Sponsored and contributed by [Cynny SpA](https://www.cynny.com/).**</div><div class="line"><a name="l00002"></a><span class="lineno"> 2</span>&#160;</div><div class="line"><a name="l00003"></a><span class="lineno"> 3</span>&#160;# uvw - libuv wrapper in modern C++</div><div class="line"><a name="l00004"></a><span class="lineno"> 4</span>&#160;</div><div class="line"><a name="l00005"></a><span class="lineno"> 5</span>&#160;[![Build Status](https://travis-ci.org/skypjack/uvw.svg?branch=master)](https://travis-ci.org/skypjack/uvw)</div><div class="line"><a name="l00006"></a><span class="lineno"> 6</span>&#160;[![Build status](https://ci.appveyor.com/api/projects/status/m5ndm8gnu8isg2to?svg=true)](https://ci.appveyor.com/project/skypjack/uvw)</div><div class="line"><a name="l00007"></a><span class="lineno"> 7</span>&#160;[![Coverage Status](https://coveralls.io/repos/github/skypjack/uvw/badge.svg?branch=master)](https://coveralls.io/github/skypjack/uvw?branch=master)</div><div class="line"><a name="l00008"></a><span class="lineno"> 8</span>&#160;[![Donate](https://img.shields.io/badge/Donate-PayPal-green.svg)](https://www.paypal.com/cgi-bin/webscr?cmd=_donations&amp;business=W2HF9FESD5LJY&amp;lc=IT&amp;item_name=Michele%20Caini&amp;currency_code=EUR&amp;bn=PP%2dDonationsBF%3abtn_donateCC_LG%2egif%3aNonHosted)</div><div class="line"><a name="l00009"></a><span class="lineno"> 9</span>&#160;</div><div class="line"><a name="l00010"></a><span class="lineno"> 10</span>&#160;# Introduction</div><div class="line"><a name="l00011"></a><span class="lineno"> 11</span>&#160;</div><div class="line"><a name="l00012"></a><span class="lineno"> 12</span>&#160;`uvw` is a header-only, event based, tiny and easy to use *libuv* wrapper in modern C++.&lt;br/&gt;</div><div class="line"><a name="l00013"></a><span class="lineno"> 13</span>&#160;The basic idea is to hide completely the *C-ish* interface of *libuv* behind a graceful C++ API. Currently, no `uv_*_t` data structure is actually exposed by the library.&lt;br/&gt;</div><div class="line"><a name="l00014"></a><span class="lineno"> 14</span>&#160;Note that `uvw` stays true to the API of *libuv* and it doesn&#39;t add anything to its interface. For the same reasons, users of the library must follow the same rules who are used to follow with *libuv*.&lt;br/&gt;</div><div class="line"><a name="l00015"></a><span class="lineno"> 15</span>&#160;As an example, a *handle* should be initialized before any other operation and closed once it is no longer in use.</div><div class="line"><a name="l00016"></a><span class="lineno"> 16</span>&#160;</div><div class="line"><a name="l00017"></a><span class="lineno"> 17</span>&#160;## Code Example</div><div class="line"><a name="l00018"></a><span class="lineno"> 18</span>&#160;</div><div class="line"><a name="l00019"></a><span class="lineno"> 19</span>&#160;```cpp</div><div class="line"><a name="l00020"></a><span class="lineno"> 20</span>&#160;#include &lt;uvw.hpp&gt;</div><div class="line"><a name="l00021"></a><span class="lineno"> 21</span>&#160;#include &lt;memory&gt;</div><div class="line"><a name="l00022"></a><span class="lineno"> 22</span>&#160;</div><div class="line"><a name="l00023"></a><span class="lineno"> 23</span>&#160;void listen(uvw::Loop &amp;loop) {</div><div class="line"><a name="l00024"></a><span class="lineno"> 24</span>&#160; std::shared_ptr&lt;uvw::TcpHandle&gt; tcp = loop.resource&lt;uvw::TcpHandle&gt;();</div><div class="line"><a name="l00025"></a><span class="lineno"> 25</span>&#160;</div><div class="line"><a name="l00026"></a><span class="lineno"> 26</span>&#160; tcp-&gt;once&lt;uvw::ListenEvent&gt;([](const uvw::ListenEvent &amp;, uvw::TcpHandle &amp;srv) {</div><div class="line"><a name="l00027"></a><span class="lineno"> 27</span>&#160; std::shared_ptr&lt;uvw::TcpHandle&gt; client = srv.loop().resource&lt;uvw::TcpHandle&gt;();</div><div class="line"><a name="l00028"></a><span class="lineno"> 28</span>&#160;</div><div class="line"><a name="l00029"></a><span class="lineno"> 29</span>&#160; client-&gt;on&lt;uvw::CloseEvent&gt;([ptr = srv.shared_from_this()](const uvw::CloseEvent &amp;, uvw::TcpHandle &amp;) { ptr-&gt;close(); });</div><div class="line"><a name="l00030"></a><span class="lineno"> 30</span>&#160; client-&gt;on&lt;uvw::EndEvent&gt;([](const uvw::EndEvent &amp;, uvw::TcpHandle &amp;client) { client.close(); });</div><div class="line"><a name="l00031"></a><span class="lineno"> 31</span>&#160;</div><div class="line"><a name="l00032"></a><span class="lineno"> 32</span>&#160; srv.accept(*client);</div><div class="line"><a name="l00033"></a><span class="lineno"> 33</span>&#160; client-&gt;read();</div><div class="line"><a name="l00034"></a><span class="lineno"> 34</span>&#160; });</div><div class="line"><a name="l00035"></a><span class="lineno"> 35</span>&#160;</div><div class="line"><a name="l00036"></a><span class="lineno"> 36</span>&#160; tcp-&gt;bind(&quot;127.0.0.1&quot;, 4242);</div><div class="line"><a name="l00037"></a><span class="lineno"> 37</span>&#160; tcp-&gt;listen();</div><div class="line"><a name="l00038"></a><span class="lineno"> 38</span>&#160;}</div><div class="line"><a name="l00039"></a><span class="lineno"> 39</span>&#160;</div><div class="line"><a name="l00040"></a><span class="lineno"> 40</span>&#160;void conn(uvw::Loop &amp;loop) {</div><div class="line"><a name="l00041"></a><span class="lineno"> 41</span>&#160; auto tcp = loop.resource&lt;uvw::TcpHandle&gt;();</div><div class="line"><a name="l00042"></a><span class="lineno"> 42</span>&#160;</div><div class="line"><a name="l00043"></a><span class="lineno"> 43</span>&#160; tcp-&gt;on&lt;uvw::ErrorEvent&gt;([](const uvw::ErrorEvent &amp;, uvw::TcpHandle &amp;) { /* handle errors */ });</div><div class="line"><a name="l00044"></a><span class="lineno"> 44</span>&#160;</div><div class="line"><a name="l00045"></a><span class="lineno"> 45</span>&#160; tcp-&gt;once&lt;uvw::ConnectEvent&gt;([](const uvw::ConnectEvent &amp;, uvw::TcpHandle &amp;tcp) {</div><div class="line"><a name="l00046"></a><span class="lineno"> 46</span>&#160; auto dataWrite = std::unique_ptr&lt;char[]&gt;(new char[2]{ &#39;b&#39;, &#39;c&#39; });</div><div class="line"><a name="l00047"></a><span class="lineno"> 47</span>&#160; tcp.write(std::move(dataWrite), 2);</div><div class="line"><a name="l00048"></a><span class="lineno"> 48</span>&#160; tcp.close();</div><div class="line"><a name="l00049"></a><span class="lineno"> 49</span>&#160; });</div><div class="line"><a name="l00050"></a><span class="lineno"> 50</span>&#160;</div><div class="line"><a name="l00051"></a><span class="lineno"> 51</span>&#160; tcp-&gt;connect(std::string{&quot;127.0.0.1&quot;}, 4242);</div><div class="line"><a name="l00052"></a><span class="lineno"> 52</span>&#160;}</div><div class="line"><a name="l00053"></a><span class="lineno"> 53</span>&#160;</div><div class="line"><a name="l00054"></a><span class="lineno"> 54</span>&#160;int main() {</div><div class="line"><a name="l00055"></a><span class="lineno"> 55</span>&#160; auto loop = uvw::Loop::getDefault();</div><div class="line"><a name="l00056"></a><span class="lineno"> 56</span>&#160; listen(*loop);</div><div class="line"><a name="l00057"></a><span class="lineno"> 57</span>&#160; conn(*loop);</div><div class="line"><a name="l00058"></a><span class="lineno"> 58</span>&#160; loop-&gt;run();</div><div class="line"><a name="l00059"></a><span class="lineno"> 59</span>&#160;}</div><div class="line"><a name="l00060"></a><span class="lineno"> 60</span>&#160;```</div><div class="line"><a name="l00061"></a><span class="lineno"> 61</span>&#160;</div><div class="line"><a name="l00062"></a><span class="lineno"> 62</span>&#160;## Motivation</div><div class="line"><a name="l00063"></a><span class="lineno"> 63</span>&#160;</div><div class="line"><a name="l00064"></a><span class="lineno"> 64</span>&#160;The main reason for which `uvw` has been written is the fact that it does not exist a valid *libuv* wrapper in C++. That&#39;s all.</div><div class="line"><a name="l00065"></a><span class="lineno"> 65</span>&#160;</div><div class="line"><a name="l00066"></a><span class="lineno"> 66</span>&#160;# Build Instructions</div><div class="line"><a name="l00067"></a><span class="lineno"> 67</span>&#160;</div><div class="line"><a name="l00068"></a><span class="lineno"> 68</span>&#160;## Requirements</div><div class="line"><a name="l00069"></a><span class="lineno"> 69</span>&#160;</div><div class="line"><a name="l00070"></a><span class="lineno"> 70</span>&#160;To be able to use `uvw`, users must provide the following system-wide tools:</div><div class="line"><a name="l00071"></a><span class="lineno"> 71</span>&#160;</div><div class="line"><a name="l00072"></a><span class="lineno"> 72</span>&#160;* A full-featured compiler that supports at least C++14.</div><div class="line"><a name="l00073"></a><span class="lineno"> 73</span>&#160;* `libuv` (which version depends on the tag of `uvw` in use).</div><div class="line"><a name="l00074"></a><span class="lineno"> 74</span>&#160;</div><div class="line"><a name="l00075"></a><span class="lineno"> 75</span>&#160;The requirements below are mandatory to compile the tests and to extract the documentation:</div><div class="line"><a name="l00076"></a><span class="lineno"> 76</span>&#160;</div><div class="line"><a name="l00077"></a><span class="lineno"> 77</span>&#160;* CMake version 3.2 or later.</div><div class="line"><a name="l00078"></a><span class="lineno"> 78</span>&#160;* Doxygen version 1.8 or later.</div><div class="line"><a name="l00079"></a><span class="lineno"> 79</span>&#160;</div><div class="line"><a name="l00080"></a><span class="lineno"> 80</span>&#160;Note that `libuv` is part of the dependencies of the project and it will be cloned by `cmake` (see below for further details).&lt;br/&gt;</div><div class="line"><a name="l00081"></a><span class="lineno"> 81</span>&#160;Because of that, users have not to install it to compile and execute the tests.</div><div class="line"><a name="l00082"></a><span class="lineno"> 82</span>&#160;</div><div class="line"><a name="l00083"></a><span class="lineno"> 83</span>&#160;## Library</div><div class="line"><a name="l00084"></a><span class="lineno"> 84</span>&#160;</div><div class="line"><a name="l00085"></a><span class="lineno"> 85</span>&#160;`uvw` is a header-only library.&lt;br/&gt;</div><div class="line"><a name="l00086"></a><span class="lineno"> 86</span>&#160;This means that including the `uvw.hpp` header or one of the other `uvw/*.hpp` headers is enough to use it.&lt;br/&gt;</div><div class="line"><a name="l00087"></a><span class="lineno"> 87</span>&#160;It&#39;s a matter of adding the following line at the top of a file:</div><div class="line"><a name="l00088"></a><span class="lineno"> 88</span>&#160;</div><div class="line"><a name="l00089"></a><span class="lineno"> 89</span>&#160;```cpp</div><div class="line"><a name="l00090"></a><span class="lineno"> 90</span>&#160;#include &lt;uvw.hpp&gt;</div><div class="line"><a name="l00091"></a><span class="lineno"> 91</span>&#160;```</div><div class="line"><a name="l00092"></a><span class="lineno"> 92</span>&#160;</div><div class="line"><a name="l00093"></a><span class="lineno"> 93</span>&#160;Then pass the proper `-I` argument to the compiler to add the `src` directory to the include paths.&lt;br/&gt;</div><div class="line"><a name="l00094"></a><span class="lineno"> 94</span>&#160;Note that users are demanded to correctly setup include directories and libraries search paths for *libuv*.</div><div class="line"><a name="l00095"></a><span class="lineno"> 95</span>&#160;</div><div class="line"><a name="l00096"></a><span class="lineno"> 96</span>&#160;## Versioning</div><div class="line"><a name="l00097"></a><span class="lineno"> 97</span>&#160;</div><div class="line"><a name="l00098"></a><span class="lineno"> 98</span>&#160;Starting with tag _v1.12.0_ of `libuv`, `uvw` follows the [semantic versioning](http://semver.org/) scheme.&lt;br/&gt;</div><div class="line"><a name="l00099"></a><span class="lineno"> 99</span>&#160;The problem is that any version of `uvw` also requires to track explicitly the version of `libuv` to which it is bound.&lt;br/&gt;</div><div class="line"><a name="l00100"></a><span class="lineno"> 100</span>&#160;Because of that, the latter wil be appended to the version of `uvw`. As an example:</div><div class="line"><a name="l00101"></a><span class="lineno"> 101</span>&#160;</div><div class="line"><a name="l00102"></a><span class="lineno"> 102</span>&#160; vU.V.W_libuv-vX.Y</div><div class="line"><a name="l00103"></a><span class="lineno"> 103</span>&#160;</div><div class="line"><a name="l00104"></a><span class="lineno"> 104</span>&#160;In particular, the following applies:</div><div class="line"><a name="l00105"></a><span class="lineno"> 105</span>&#160;</div><div class="line"><a name="l00106"></a><span class="lineno"> 106</span>&#160;* _U.V.W_ are major, minor and patch versions of `uvw`.</div><div class="line"><a name="l00107"></a><span class="lineno"> 107</span>&#160;* _X.Y_ is the version of `libuv` to which to refer (where any patch version is valid).</div><div class="line"><a name="l00108"></a><span class="lineno"> 108</span>&#160;</div><div class="line"><a name="l00109"></a><span class="lineno"> 109</span>&#160;In other terms, tags will look like this from now on:</div><div class="line"><a name="l00110"></a><span class="lineno"> 110</span>&#160;</div><div class="line"><a name="l00111"></a><span class="lineno"> 111</span>&#160; v1.0.0_libuv-v1.12</div><div class="line"><a name="l00112"></a><span class="lineno"> 112</span>&#160;</div><div class="line"><a name="l00113"></a><span class="lineno"> 113</span>&#160;Branch `master` of `uvw` will be a work in progress branch that follows branch _v1.x_ of `libuv` (at least as long as it remains their _master_ branch).&lt;br/&gt;</div><div class="line"><a name="l00114"></a><span class="lineno"> 114</span>&#160;</div><div class="line"><a name="l00115"></a><span class="lineno"> 115</span>&#160;## Documentation</div><div class="line"><a name="l00116"></a><span class="lineno"> 116</span>&#160;</div><div class="line"><a name="l00117"></a><span class="lineno"> 117</span>&#160;The documentation is based on [`doxygen`](http://www.stack.nl/~dimitri/doxygen/). To build it:</div><div class="line"><a name="l00118"></a><span class="lineno"> 118</span>&#160;</div><div class="line"><a name="l00119"></a><span class="lineno"> 119</span>&#160;* `$ cd build`</div><div class="line"><a name="l00120"></a><span class="lineno"> 120</span>&#160;* `$ cmake ..`</div><div class="line"><a name="l00121"></a><span class="lineno"> 121</span>&#160;* `$ make docs`</div><div class="line"><a name="l00122"></a><span class="lineno"> 122</span>&#160;</div><div class="line"><a name="l00123"></a><span class="lineno"> 123</span>&#160;The API reference will be created in HTML format within the directory `build/docs/html`.&lt;br/&gt;</div><div class="line"><a name="l00124"></a><span class="lineno"> 124</span>&#160;To navigate it with your favorite browser:</div><div class="line"><a name="l00125"></a><span class="lineno"> 125</span>&#160;</div><div class="line"><a name="l00126"></a><span class="lineno"> 126</span>&#160;* `$ cd build`</div><div class="line"><a name="l00127"></a><span class="lineno"> 127</span>&#160;* `$ your_favorite_browser docs/html/index.html`</div><div class="line"><a name="l00128"></a><span class="lineno"> 128</span>&#160;</div><div class="line"><a name="l00129"></a><span class="lineno"> 129</span>&#160;The API reference is also available [online](https://skypjack.github.io/uvw/) for the latest version.</div><div class="line"><a name="l00130"></a><span class="lineno"> 130</span>&#160;</div><div class="line"><a name="l00131"></a><span class="lineno"> 131</span>&#160;### Note</div><div class="line"><a name="l00132"></a><span class="lineno"> 132</span>&#160;</div><div class="line"><a name="l00133"></a><span class="lineno"> 133</span>&#160;The documentation is mostly inspired by the official [libuv API documentation](http://docs.libuv.org/en/v1.x/) for obvious reasons.&lt;br/&gt;</div><div class="line"><a name="l00134"></a><span class="lineno"> 134</span>&#160;If you are mainly interested in the way `uvw` imports `libuv` in a `cmake` based project, I suggest you to take a look at [this](https://github.com/skypjack/libuv_cmake) repository instead.</div><div class="line"><a name="l00135"></a><span class="lineno"> 135</span>&#160;</div><div class="line"><a name="l00136"></a><span class="lineno"> 136</span>&#160;## Tests</div><div class="line"><a name="l00137"></a><span class="lineno"> 137</span>&#160;</div><div class="line"><a name="l00138"></a><span class="lineno"> 138</span>&#160;To compile and run the tests, `uvw` requires *libuv* and *googletest*.&lt;br/&gt;</div><div class="line"><a name="l00139"></a><span class="lineno"> 139</span>&#160;`cmake` will download and compile both the libraries before to compile anything else.</div><div class="line"><a name="l00140"></a><span class="lineno"> 140</span>&#160;</div><div class="line"><a name="l00141"></a><span class="lineno"> 141</span>&#160;To build the tests:</div><div class="line"><a name="l00142"></a><span class="lineno"> 142</span>&#160;</div><div class="line"><a name="l00143"></a><span class="lineno"> 143</span>&#160;* `$ cd build`</div><div class="line"><a name="l00144"></a><span class="lineno"> 144</span>&#160;* `$ cmake ..`</div><div class="line"><a name="l00145"></a><span class="lineno"> 145</span>&#160;* `$ make`</div><div class="line"><a name="l00146"></a><span class="lineno"> 146</span>&#160;* `$ make test`</div><div class="line"><a name="l00147"></a><span class="lineno"> 147</span>&#160;</div><div class="line"><a name="l00148"></a><span class="lineno"> 148</span>&#160;# Crash Course</div><div class="line"><a name="l00149"></a><span class="lineno"> 149</span>&#160;</div><div class="line"><a name="l00150"></a><span class="lineno"> 150</span>&#160;## Vademecum</div><div class="line"><a name="l00151"></a><span class="lineno"> 151</span>&#160;</div><div class="line"><a name="l00152"></a><span class="lineno"> 152</span>&#160;There is only one rule when using `uvw`: always initialize the resources and terminate them.</div><div class="line"><a name="l00153"></a><span class="lineno"> 153</span>&#160;</div><div class="line"><a name="l00154"></a><span class="lineno"> 154</span>&#160;Resources belong mainly to two families: _handles_ and _requests_.&lt;br/&gt;</div><div class="line"><a name="l00155"></a><span class="lineno"> 155</span>&#160;Handles represent long-lived objects capable of performing certain operations while active.&lt;br/&gt;</div><div class="line"><a name="l00156"></a><span class="lineno"> 156</span>&#160;Requests represent (typically) short-lived operations performed either over a handle or standalone.</div><div class="line"><a name="l00157"></a><span class="lineno"> 157</span>&#160;</div><div class="line"><a name="l00158"></a><span class="lineno"> 158</span>&#160;The following sections will explain in short what it means to initialize and terminate these kinds of resources.&lt;br/&gt;</div><div class="line"><a name="l00159"></a><span class="lineno"> 159</span>&#160;For more details, please refer to the [online documentation](https://skypjack.github.io/uvw/).</div><div class="line"><a name="l00160"></a><span class="lineno"> 160</span>&#160;</div><div class="line"><a name="l00161"></a><span class="lineno"> 161</span>&#160;## Handles</div><div class="line"><a name="l00162"></a><span class="lineno"> 162</span>&#160;</div><div class="line"><a name="l00163"></a><span class="lineno"> 163</span>&#160;Initialization is usually performed under the hood and can be even passed over, as far as handles are created using the `Loop::resource` member function.&lt;br/&gt;</div><div class="line"><a name="l00164"></a><span class="lineno"> 164</span>&#160;On the other side, handles keep themselves alive until one explicitly closes them. Because of that, memory usage will grow up if users simply forget about a handle.&lt;br/&gt;</div><div class="line"><a name="l00165"></a><span class="lineno"> 165</span>&#160;Therefore the rule quickly becomes *always close your handles*. It&#39;s as simple as calling the `close` member function on them.</div><div class="line"><a name="l00166"></a><span class="lineno"> 166</span>&#160;</div><div class="line"><a name="l00167"></a><span class="lineno"> 167</span>&#160;## Requests</div><div class="line"><a name="l00168"></a><span class="lineno"> 168</span>&#160;</div><div class="line"><a name="l00169"></a><span class="lineno"> 169</span>&#160;Usually initializing a request object is not required. Anyway, the recommended way to create a request is still through the `Loop::resource` member function.&lt;br/&gt;</div><div class="line"><a name="l00170"></a><span class="lineno"> 170</span>&#160;Requests will keep themselves alive as long as they are bound to unfinished underlying activities. This means that users have not to discard explicitly a request.&lt;br/&gt;</div><div class="line"><a name="l00171"></a><span class="lineno"> 171</span>&#160;Therefore the rule quickly becomes *feel free to make a request and forget about it*. It&#39;s as simple as calling a member function on them.</div><div class="line"><a name="l00172"></a><span class="lineno"> 172</span>&#160;</div><div class="line"><a name="l00173"></a><span class="lineno"> 173</span>&#160;## The Loop and the Resource</div><div class="line"><a name="l00174"></a><span class="lineno"> 174</span>&#160;</div><div class="line"><a name="l00175"></a><span class="lineno"> 175</span>&#160;The first thing to do to use `uvw` is to create a loop. In case the default one is enough, it&#39;s easy as doing this:</div><div class="line"><a name="l00176"></a><span class="lineno"> 176</span>&#160;</div><div class="line"><a name="l00177"></a><span class="lineno"> 177</span>&#160;```cpp</div><div class="line"><a name="l00178"></a><span class="lineno"> 178</span>&#160;auto loop = uvw::Loop::getDefault();</div><div class="line"><a name="l00179"></a><span class="lineno"> 179</span>&#160;```</div><div class="line"><a name="l00180"></a><span class="lineno"> 180</span>&#160;</div><div class="line"><a name="l00181"></a><span class="lineno"> 181</span>&#160;Note that loop objects don&#39;t require to be closed explicitly, even if they offer the `close` member function in case an user wants to do that.&lt;br/&gt;</div><div class="line"><a name="l00182"></a><span class="lineno"> 182</span>&#160;Loops can be started using the `run` member function. The two calls below are equivalent:</div><div class="line"><a name="l00183"></a><span class="lineno"> 183</span>&#160;</div><div class="line"><a name="l00184"></a><span class="lineno"> 184</span>&#160;```cpp</div><div class="line"><a name="l00185"></a><span class="lineno"> 185</span>&#160;loop-&gt;run();</div><div class="line"><a name="l00186"></a><span class="lineno"> 186</span>&#160;loop-&gt;run&lt;uvw::Loop::Mode::DEFAULT&gt;</div><div class="line"><a name="l00187"></a><span class="lineno"> 187</span>&#160;```</div><div class="line"><a name="l00188"></a><span class="lineno"> 188</span>&#160;</div><div class="line"><a name="l00189"></a><span class="lineno"> 189</span>&#160;Available modes are: `DEFAULT`, `ONCE`, `NOWAIT`. Please refer to the documentation of *libuv* for further details.</div><div class="line"><a name="l00190"></a><span class="lineno"> 190</span>&#160;</div><div class="line"><a name="l00191"></a><span class="lineno"> 191</span>&#160;In order to create a resource and to bind it to the given loop, just do the following:</div><div class="line"><a name="l00192"></a><span class="lineno"> 192</span>&#160;</div><div class="line"><a name="l00193"></a><span class="lineno"> 193</span>&#160;```cpp</div><div class="line"><a name="l00194"></a><span class="lineno"> 194</span>&#160;auto tcp = loop.resource&lt;uvw::TcpHandle&gt;();</div><div class="line"><a name="l00195"></a><span class="lineno"> 195</span>&#160;```</div><div class="line"><a name="l00196"></a><span class="lineno"> 196</span>&#160;</div><div class="line"><a name="l00197"></a><span class="lineno"> 197</span>&#160;The line above will create and initialize a tcp handle, then a shared pointer to that resource will be returned.&lt;br/&gt;</div><div class="line"><a name="l00198"></a><span class="lineno"> 198</span>&#160;Users should check if pointers have been correctly initialized: in case of errors, they won&#39;t be.&lt;br/&gt;</div><div class="line"><a name="l00199"></a><span class="lineno"> 199</span>&#160;Another way to create a resource is:</div><div class="line"><a name="l00200"></a><span class="lineno"> 200</span>&#160;</div><div class="line"><a name="l00201"></a><span class="lineno"> 201</span>&#160;```cpp</div><div class="line"><a name="l00202"></a><span class="lineno"> 202</span>&#160;auto tcp = TcpHandle::create(loop);</div><div class="line"><a name="l00203"></a><span class="lineno"> 203</span>&#160;tcp-&gt;init();</div><div class="line"><a name="l00204"></a><span class="lineno"> 204</span>&#160;```</div><div class="line"><a name="l00205"></a><span class="lineno"> 205</span>&#160;</div><div class="line"><a name="l00206"></a><span class="lineno"> 206</span>&#160;Pretty annoying indeed. Using a loop is the recommended approach.</div><div class="line"><a name="l00207"></a><span class="lineno"> 207</span>&#160;</div><div class="line"><a name="l00208"></a><span class="lineno"> 208</span>&#160;The resources also accept arbitrary user-data that won&#39;t be touched in any case.&lt;br/&gt;</div><div class="line"><a name="l00209"></a><span class="lineno"> 209</span>&#160;Users can set and get them through the `data` member function as it follows:</div><div class="line"><a name="l00210"></a><span class="lineno"> 210</span>&#160;</div><div class="line"><a name="l00211"></a><span class="lineno"> 211</span>&#160;```cpp</div><div class="line"><a name="l00212"></a><span class="lineno"> 212</span>&#160;resource-&gt;data(std::make_shared&lt;int&gt;(42));</div><div class="line"><a name="l00213"></a><span class="lineno"> 213</span>&#160;std::shared_ptr&lt;void&gt; data = resource-&gt;data();</div><div class="line"><a name="l00214"></a><span class="lineno"> 214</span>&#160;```</div><div class="line"><a name="l00215"></a><span class="lineno"> 215</span>&#160;</div><div class="line"><a name="l00216"></a><span class="lineno"> 216</span>&#160;Resources expect a `std::shared_pointer&lt;void&gt;` and return it, therefore any kind of data is welcome.&lt;br/&gt;</div><div class="line"><a name="l00217"></a><span class="lineno"> 217</span>&#160;Users can explicitly specify a type other than `void` when calling the `data` member function:</div><div class="line"><a name="l00218"></a><span class="lineno"> 218</span>&#160;</div><div class="line"><a name="l00219"></a><span class="lineno"> 219</span>&#160;```cpp</div><div class="line"><a name="l00220"></a><span class="lineno"> 220</span>&#160;std::shared_ptr&lt;int&gt; data = resource-&gt;data&lt;int&gt;();</div><div class="line"><a name="l00221"></a><span class="lineno"> 221</span>&#160;```</div><div class="line"><a name="l00222"></a><span class="lineno"> 222</span>&#160;</div><div class="line"><a name="l00223"></a><span class="lineno"> 223</span>&#160;Remember from the previous section that a handle will keep itself alive until one invokes the `close` member function on it.&lt;br/&gt;</div><div class="line"><a name="l00224"></a><span class="lineno"> 224</span>&#160;To know what are the handles that are still alive and bound to a given loop, just do the following:</div><div class="line"><a name="l00225"></a><span class="lineno"> 225</span>&#160;</div><div class="line"><a name="l00226"></a><span class="lineno"> 226</span>&#160;```cpp</div><div class="line"><a name="l00227"></a><span class="lineno"> 227</span>&#160;loop.walk([](uvw::BaseHandle &amp;){ /* application code here */ });</div><div class="line"><a name="l00228"></a><span class="lineno"> 228</span>&#160;```</div><div class="line"><a name="l00229"></a><span class="lineno"> 229</span>&#160;</div><div class="line"><a name="l00230"></a><span class="lineno"> 230</span>&#160;`BaseHandle` exposes a few methods and cannot be promoted to the original type of the handle (even though `type` and `category` member functions fill the gap somehow).&lt;br/&gt;</div><div class="line"><a name="l00231"></a><span class="lineno"> 231</span>&#160;Anyway, it can be used to close the handle that originated from it. As an example, all the pending handles can be closed easily as it follows:</div><div class="line"><a name="l00232"></a><span class="lineno"> 232</span>&#160;</div><div class="line"><a name="l00233"></a><span class="lineno"> 233</span>&#160;```cpp</div><div class="line"><a name="l00234"></a><span class="lineno"> 234</span>&#160;loop.walk([](uvw::BaseHandle &amp;h){ h.close(); });</div><div class="line"><a name="l00235"></a><span class="lineno"> 235</span>&#160;```</div><div class="line"><a name="l00236"></a><span class="lineno"> 236</span>&#160;</div><div class="line"><a name="l00237"></a><span class="lineno"> 237</span>&#160;No need to keep track of them.</div><div class="line"><a name="l00238"></a><span class="lineno"> 238</span>&#160;</div><div class="line"><a name="l00239"></a><span class="lineno"> 239</span>&#160;To know what are the available resources&#39; types, please refer the API reference.</div><div class="line"><a name="l00240"></a><span class="lineno"> 240</span>&#160;</div><div class="line"><a name="l00241"></a><span class="lineno"> 241</span>&#160;## The event-based approach</div><div class="line"><a name="l00242"></a><span class="lineno"> 242</span>&#160;</div><div class="line"><a name="l00243"></a><span class="lineno"> 243</span>&#160;For `uvw` offers an event-based approach, resources are small event emitters to which listeners can be attached.&lt;br/&gt;</div><div class="line"><a name="l00244"></a><span class="lineno"> 244</span>&#160;Attaching a listener to a resource is the recommended way to be notified about changes.&lt;br/&gt;</div><div class="line"><a name="l00245"></a><span class="lineno"> 245</span>&#160;Listeners must be callable objects of type `void(EventType &amp;, ResourceType &amp;)`, where:</div><div class="line"><a name="l00246"></a><span class="lineno"> 246</span>&#160;</div><div class="line"><a name="l00247"></a><span class="lineno"> 247</span>&#160;* `EventType` is the type of the event for which they have been designed.</div><div class="line"><a name="l00248"></a><span class="lineno"> 248</span>&#160;* `ResourceType` is the type of the resource that has originated the event.</div><div class="line"><a name="l00249"></a><span class="lineno"> 249</span>&#160;</div><div class="line"><a name="l00250"></a><span class="lineno"> 250</span>&#160;It means that the following function types are all valid:</div><div class="line"><a name="l00251"></a><span class="lineno"> 251</span>&#160;</div><div class="line"><a name="l00252"></a><span class="lineno"> 252</span>&#160;* `void(EventType &amp;, ResourceType &amp;)`</div><div class="line"><a name="l00253"></a><span class="lineno"> 253</span>&#160;* `void(const EventType &amp;, ResourceType &amp;)`</div><div class="line"><a name="l00254"></a><span class="lineno"> 254</span>&#160;* `void(EventType &amp;, const ResourceType &amp;)`</div><div class="line"><a name="l00255"></a><span class="lineno"> 255</span>&#160;* `void(const EventType &amp;, const ResourceType &amp;)`</div><div class="line"><a name="l00256"></a><span class="lineno"> 256</span>&#160;</div><div class="line"><a name="l00257"></a><span class="lineno"> 257</span>&#160;Once more, please note that there is no need to keep around references to the resources: they will pass themselves as an argument whenever an event is published.</div><div class="line"><a name="l00258"></a><span class="lineno"> 258</span>&#160;</div><div class="line"><a name="l00259"></a><span class="lineno"> 259</span>&#160;There exist two methods to attach an event to a resource:</div><div class="line"><a name="l00260"></a><span class="lineno"> 260</span>&#160;</div><div class="line"><a name="l00261"></a><span class="lineno"> 261</span>&#160;* `resource.once&lt;EventType&gt;(listener)`: the listener will be automatically removed after the first event of the given type.</div><div class="line"><a name="l00262"></a><span class="lineno"> 262</span>&#160;* `resource.on&lt;EventType&gt;(listener)`: to be used for long-running listeners.</div><div class="line"><a name="l00263"></a><span class="lineno"> 263</span>&#160;</div><div class="line"><a name="l00264"></a><span class="lineno"> 264</span>&#160;Both of them return an object of type `ResourceType::Connection` (as an example, `TcpHandle::Connection`).&lt;br/&gt;</div><div class="line"><a name="l00265"></a><span class="lineno"> 265</span>&#160;A connection object can be used later as an argument to the `erase` member function of the resource to remove the listener.&lt;br/&gt;</div><div class="line"><a name="l00266"></a><span class="lineno"> 266</span>&#160;There exists also the `clear` member function to drop all the listeners at once.</div><div class="line"><a name="l00267"></a><span class="lineno"> 267</span>&#160;</div><div class="line"><a name="l00268"></a><span class="lineno"> 268</span>&#160;Almost all the resources use to emit `ErrorEvent` events in case of errors.&lt;br/&gt;</div><div class="line"><a name="l00269"></a><span class="lineno"> 269</span>&#160;All the other events are specific for the given resource and documented in the API reference.</div><div class="line"><a name="l00270"></a><span class="lineno"> 270</span>&#160;</div><div class="line"><a name="l00271"></a><span class="lineno"> 271</span>&#160;The code below shows how to create a simple tcp server using `uvw`:</div><div class="line"><a name="l00272"></a><span class="lineno"> 272</span>&#160;</div><div class="line"><a name="l00273"></a><span class="lineno"> 273</span>&#160;```cpp</div><div class="line"><a name="l00274"></a><span class="lineno"> 274</span>&#160;auto loop = uvw::Loop::getDefault();</div><div class="line"><a name="l00275"></a><span class="lineno"> 275</span>&#160;auto tcp = loop.resource&lt;uvw::TcpHandle&gt;();</div><div class="line"><a name="l00276"></a><span class="lineno"> 276</span>&#160;</div><div class="line"><a name="l00277"></a><span class="lineno"> 277</span>&#160;tcp-&gt;on&lt;uvw::ErrorEvent&gt;([](const uvw::ErrorEvent &amp;, uvw::TcpHandle &amp;) { /* something went wrong */ });</div><div class="line"><a name="l00278"></a><span class="lineno"> 278</span>&#160;</div><div class="line"><a name="l00279"></a><span class="lineno"> 279</span>&#160;tcp-&gt;on&lt;uvw::ListenEvent&gt;([](const uvw::ListenEvent &amp;, uvw::TcpHandle &amp;srv) {</div><div class="line"><a name="l00280"></a><span class="lineno"> 280</span>&#160; std::shared_ptr&lt;uvw::TcpHandle&gt; client = srv.loop().resource&lt;uvw::TcpHandle&gt;();</div><div class="line"><a name="l00281"></a><span class="lineno"> 281</span>&#160; client-&gt;once&lt;uvw::EndEvent&gt;([](const uvw::EndEvent &amp;, uvw::TcpHandle &amp;client) { client.close(); });</div><div class="line"><a name="l00282"></a><span class="lineno"> 282</span>&#160; client-&gt;on&lt;uvw::DataEvent&gt;([](const uvw::DataEvent &amp;, uvw::TcpHandle &amp;) { /* data received */ });</div><div class="line"><a name="l00283"></a><span class="lineno"> 283</span>&#160; srv.accept(*client);</div><div class="line"><a name="l00284"></a><span class="lineno"> 284</span>&#160; client-&gt;read();</div><div class="line"><a name="l00285"></a><span class="lineno"> 285</span>&#160;});</div><div class="line"><a name="l00286"></a><span class="lineno"> 286</span>&#160;</div><div class="line"><a name="l00287"></a><span class="lineno"> 287</span>&#160;tcp-&gt;bind(&quot;127.0.0.1&quot;, 4242);</div><div class="line"><a name="l00288"></a><span class="lineno"> 288</span>&#160;tcp-&gt;listen();</div><div class="line"><a name="l00289"></a><span class="lineno"> 289</span>&#160;```</div><div class="line"><a name="l00290"></a><span class="lineno"> 290</span>&#160;</div><div class="line"><a name="l00291"></a><span class="lineno"> 291</span>&#160;Note also that `uvw::TcpHandle` already supports _IPv6_ out-of-the-box. The statement above is equivalent to `tcp-&gt;bind&lt;uvw::IPv4&gt;(&quot;127.0.0.1&quot;, 4242)`.&lt;br/&gt;</div><div class="line"><a name="l00292"></a><span class="lineno"> 292</span>&#160;It&#39;s suffice to explicitly specify `uvw::IPv6` as the underlying protocol to use it.</div><div class="line"><a name="l00293"></a><span class="lineno"> 293</span>&#160;</div><div class="line"><a name="l00294"></a><span class="lineno"> 294</span>&#160;The API reference is the recommended documentation for further details about resources and their methods.</div><div class="line"><a name="l00295"></a><span class="lineno"> 295</span>&#160;</div><div class="line"><a name="l00296"></a><span class="lineno"> 296</span>&#160;# Contributors</div><div class="line"><a name="l00297"></a><span class="lineno"> 297</span>&#160;</div><div class="line"><a name="l00298"></a><span class="lineno"> 298</span>&#160;If you want to contribute, please send patches as pull requests against the branch master.&lt;br/&gt;</div><div class="line"><a name="l00299"></a><span class="lineno"> 299</span>&#160;Check the [contributors list](https://github.com/skypjack/uvw/blob/master/AUTHORS) to see who has partecipated so far.</div><div class="line"><a name="l00300"></a><span class="lineno"> 300</span>&#160;</div><div class="line"><a name="l00301"></a><span class="lineno"> 301</span>&#160;# Projects that use `uvw`</div><div class="line"><a name="l00302"></a><span class="lineno"> 302</span>&#160;</div><div class="line"><a name="l00303"></a><span class="lineno"> 303</span>&#160;Below an incomplete list of projects that use `uvw`:</div><div class="line"><a name="l00304"></a><span class="lineno"> 304</span>&#160;</div><div class="line"><a name="l00305"></a><span class="lineno"> 305</span>&#160;* Internal tools (not publicly available) at **[Cynny SpA](https://www.morphcast.com/)** and **[Cynny Space](http://www.cynnyspace.com/)**.</div><div class="line"><a name="l00306"></a><span class="lineno"> 306</span>&#160;* **[Calaos.fr](https://www.calaos.fr/en/)** (Open source home automation) on [GitHub](https://github.com/calaos).</div><div class="line"><a name="l00307"></a><span class="lineno"> 307</span>&#160;* **[Iroha](http://iroha.tech/en/) - A simple, decentralized ledger** on [Github](https://github.com/hyperledger/iroha).</div><div class="line"><a name="l00308"></a><span class="lineno"> 308</span>&#160;* **Iroha blockchain core** on [Github](https://github.com/finshield/iroha-core).</div><div class="line"><a name="l00309"></a><span class="lineno"> 309</span>&#160;* **Ecwid Console Downloader** on [GitHub](https://github.com/dvetutnev/Ecwid-Console-downloader).</div><div class="line"><a name="l00310"></a><span class="lineno"> 310</span>&#160;* **Simple network ping pong for lazy students** on [GitHub](https://github.com/dvetutnev/ping_pong).</div><div class="line"><a name="l00311"></a><span class="lineno"> 311</span>&#160;</div><div class="line"><a name="l00312"></a><span class="lineno"> 312</span>&#160;If you know of other projects that use `libuv` through `uvw`, feel free to open a PR and I&#39;ll be glad to add them to the list.</div><div class="line"><a name="l00313"></a><span class="lineno"> 313</span>&#160;</div><div class="line"><a name="l00314"></a><span class="lineno"> 314</span>&#160;# License</div><div class="line"><a name="l00315"></a><span class="lineno"> 315</span>&#160;</div><div class="line"><a name="l00316"></a><span class="lineno"> 316</span>&#160;Code and documentation Copyright (c) 2017 Michele Caini.&lt;br/&gt;</div><div class="line"><a name="l00317"></a><span class="lineno"> 317</span>&#160;Code released under [the MIT license](https://github.com/skypjack/uvw/blob/master/LICENSE).&lt;br/&gt;</div><div class="line"><a name="l00318"></a><span class="lineno"> 318</span>&#160;Docs released under [Creative Commons](https://github.com/skypjack/uvw/blob/master/docs/LICENSE).</div><div class="line"><a name="l00319"></a><span class="lineno"> 319</span>&#160;</div><div class="line"><a name="l00320"></a><span class="lineno"> 320</span>&#160;# Donation</div><div class="line"><a name="l00321"></a><span class="lineno"> 321</span>&#160;</div><div class="line"><a name="l00322"></a><span class="lineno"> 322</span>&#160;Developing and maintaining `uvw` takes some time and lots of coffee. It still lacks a proper test suite, documentation is partially incomplete and not all functionalities have been fully implemented yet.&lt;br/&gt;</div><div class="line"><a name="l00323"></a><span class="lineno"> 323</span>&#160;If you want to support this project, you can offer me an espresso. I&#39;m from Italy, we&#39;re used to turning the best coffee ever in code. If you find that it&#39;s not enough, feel free to support me the way you prefer.&lt;br/&gt;</div><div class="line"><a name="l00324"></a><span class="lineno"> 324</span>&#160;Take a look at the donation button at the top of the page for more details or just click [here](https://www.paypal.com/cgi-bin/webscr?cmd=_donations&amp;business=W2HF9FESD5LJY&amp;lc=IT&amp;item_name=Michele%20Caini&amp;currency_code=EUR&amp;bn=PP%2dDonationsBF%3abtn_donateCC_LG%2egif%3aNonHosted).</div></div><!-- fragment --></div><!-- contents -->
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