data/cache/4/4e30f1a18e08341475fd9fb1d207e30d.xhtml

   1
   2
   3
   4 <h1><a name="go" id="go">Go</a></h1>
   5 <div class="level1">
   6
   7 <p>
   8
   9 <a href="http://golang.org/" class="urlextern" title="http://golang.org/"  rel="nofollow">Go</a>: <a href="http://en.wikipedia.org/wiki/Go_(programming_language)" class="interwiki iw_wp" title="http://en.wikipedia.org/wiki/Go_(programming_language)">Go</a>
  10 </p>
  11 <div class="plugin_uparrow">
  12   <a href="#" title="Back to top">
  13     <img src="lib/plugins/uparrow/images/tango-small.png" alt="Back to top"/>
  14   </a>
  15 </div>
  16
  17 </div>
  18 <!-- SECTION "Go" [1-82] -->
  19 <h2><a name="examples" id="examples">Examples</a></h2>
  20 <div class="level2">
  21 <dl class="file">
  22 <dt><a href="/~kssilveira/site/doku.php?do=export_code&amp;id=main:go&amp;codeblock=0" title="Download Snippet" class="mediafile mf_">makefile</a></dt>
  23 <dd><pre class="code file make">PROG <span class="sy0">=</span> prog_name
  24 &nbsp;
  25 all<span class="sy0">:</span> <span class="sy0">$</span><span class="br0">&#40;</span><span class="re2">PROG</span><span class="br0">&#41;</span>
  26 &nbsp;
  27 <span class="sy0">%:</span> <span class="sy0">%.</span>8
  28         8l <span class="sy0">-</span>o <span class="re0">$@</span> <span class="re0">$&lt;</span>
  29 &nbsp;
  30 <span class="sy0">%.</span>8<span class="sy0">:</span> <span class="sy0">%.</span>go
  31         8g <span class="re0">$&lt;</span></pre>
  32 </dd></dl>
  33 <dl class="file">
  34 <dt><a href="/~kssilveira/site/doku.php?do=export_code&amp;id=main:go&amp;codeblock=1" title="Download Snippet" class="mediafile mf_go">hello.go</a></dt>
  35 <dd><pre class="code file c"><span class="coMULTI">/* hello */</span>
  36 &nbsp;
  37 package main <span class="co1">// executável principal sempre deve pertencer a este pacote</span>
  38 &nbsp;
  39 import . <span class="st0">&quot;fmt&quot;</span> <span class="co1">// importa funções de saída formatada (Printf)</span>
  40 &nbsp;
  41 <span class="co1">// função principal (como em C)</span>
  42 func main<span class="br0">&#40;</span><span class="br0">&#41;</span> <span class="br0">&#123;</span>
  43         <span class="co1">//sem o . no import teríamos que utilizar fmt.Printf</span>
  44         Printf<span class="br0">&#40;</span><span class="st0">&quot;hello, world<span class="es1">\n</span>&quot;</span><span class="br0">&#41;</span>
  45 <span class="br0">&#125;</span></pre>
  46 </dd></dl>
  47 <dl class="file">
  48 <dt><a href="/~kssilveira/site/doku.php?do=export_code&amp;id=main:go&amp;codeblock=2" title="Download Snippet" class="mediafile mf_go">producer_consumer.go</a></dt>
  49 <dd><pre class="code file c"><span class="coMULTI">/* pc_channel_multi.go */</span>
  50 &nbsp;
  51 package main
  52 &nbsp;
  53 import <span class="br0">&#40;</span>
  54         . <span class="st0">&quot;fmt&quot;</span>
  55         <span class="st0">&quot;crypto/rand&quot;</span>
  56         <span class="st0">&quot;time&quot;</span>
  57         <span class="st0">&quot;flag&quot;</span>
  58 <span class="br0">&#41;</span>
  59 &nbsp;
  60 func random_between <span class="br0">&#40;</span>begin<span class="sy0">,</span> end int64<span class="br0">&#41;</span> int64 <span class="br0">&#123;</span>
  61         random_byte <span class="sy0">:=</span> make<span class="br0">&#40;</span><span class="br0">&#91;</span><span class="br0">&#93;</span>byte<span class="sy0">,</span> 1<span class="br0">&#41;</span>
  62         rand.<span class="me1">Read</span><span class="br0">&#40;</span>random_byte<span class="br0">&#41;</span>
  63         <span class="kw1">return</span> int64<span class="br0">&#40;</span>random_byte<span class="br0">&#91;</span>0<span class="br0">&#93;</span><span class="br0">&#41;</span> <span class="sy0">%</span> <span class="br0">&#40;</span>end <span class="sy0">-</span> begin <span class="sy0">+</span> 1<span class="br0">&#41;</span> <span class="sy0">+</span> begin
  64 <span class="br0">&#125;</span>
  65 &nbsp;
  66 func random_sleep <span class="br0">&#40;</span><span class="br0">&#41;</span> <span class="br0">&#123;</span>
  67         time.<span class="me1">Sleep</span><span class="br0">&#40;</span>random_between<span class="br0">&#40;</span>0<span class="sy0">,</span> <span class="sy0">*</span>MAX_SLEEP_TIME<span class="br0">&#41;</span> <span class="sy0">*</span> 10e7<span class="br0">&#41;</span>
  68 <span class="br0">&#125;</span>
  69 &nbsp;
  70 func send <span class="br0">&#40;</span>channel chan <span class="kw4">int</span><span class="sy0">,</span> i <span class="kw4">int</span><span class="br0">&#41;</span> <span class="br0">&#123;</span>
  71         channel <span class="sy0">&lt;-</span> i
  72 <span class="br0">&#125;</span>
  73 &nbsp;
  74 func recv <span class="br0">&#40;</span>channel chan <span class="kw4">int</span><span class="br0">&#41;</span> <span class="kw4">int</span> <span class="br0">&#123;</span>
  75         <span class="kw1">return</span> <span class="sy0">&lt;-</span>channel
  76 <span class="br0">&#125;</span>
  77 &nbsp;
  78 func signal <span class="br0">&#40;</span>channel chan <span class="kw4">int</span><span class="br0">&#41;</span> <span class="br0">&#123;</span>
  79         <span class="kw1">if</span> len<span class="br0">&#40;</span>channel<span class="br0">&#41;</span> <span class="sy0">&lt;</span> cap<span class="br0">&#40;</span>channel<span class="br0">&#41;</span> <span class="sy0">||</span> cap<span class="br0">&#40;</span>channel<span class="br0">&#41;</span> <span class="sy0">==</span> 0 <span class="br0">&#123;</span>
  80                 channel <span class="sy0">&lt;-</span> 0
  81         <span class="br0">&#125;</span>
  82 <span class="br0">&#125;</span>
  83 &nbsp;
  84 func wait <span class="br0">&#40;</span>channel chan <span class="kw4">int</span><span class="br0">&#41;</span> <span class="br0">&#123;</span>
  85         <span class="sy0">&lt;-</span>channel
  86 <span class="br0">&#125;</span>
  87 &nbsp;
  88 var <span class="br0">&#40;</span>
  89         BUFFER_SIZE <span class="sy0">=</span> flag.<span class="me1">Int</span><span class="br0">&#40;</span><span class="st0">&quot;s&quot;</span><span class="sy0">,</span> <span class="nu0">5</span><span class="sy0">,</span> <span class="st0">&quot;BUFFER_SIZE&quot;</span><span class="br0">&#41;</span> <span class="co1">// flag -s</span>
  90         MAX_SLEEP_TIME <span class="sy0">=</span> flag.<span class="me1">Int64</span><span class="br0">&#40;</span><span class="st0">&quot;t&quot;</span><span class="sy0">,</span> <span class="nu0">5</span><span class="sy0">,</span> <span class="st0">&quot;MAX_SLEEP_TIME&quot;</span><span class="br0">&#41;</span> <span class="co1">// flag -t</span>
  91         MAX_PRODUCTIONS <span class="sy0">=</span> flag.<span class="me1">Int</span><span class="br0">&#40;</span><span class="st0">&quot;m&quot;</span><span class="sy0">,</span> <span class="nu0">0</span><span class="sy0">,</span> <span class="st0">&quot;MAX_PRODUCTIONS, 0 for infinity&quot;</span><span class="br0">&#41;</span> <span class="co1">// flag -m</span>
  92         N_PRODUCERS <span class="sy0">=</span> flag.<span class="me1">Int</span><span class="br0">&#40;</span><span class="st0">&quot;p&quot;</span><span class="sy0">,</span> <span class="nu0">3</span><span class="sy0">,</span> <span class="st0">&quot;N_PRODUCERS&quot;</span><span class="br0">&#41;</span> <span class="co1">// flag -p</span>
  93         N_CONSUMERS <span class="sy0">=</span> flag.<span class="me1">Int</span><span class="br0">&#40;</span><span class="st0">&quot;c&quot;</span><span class="sy0">,</span> <span class="nu0">3</span><span class="sy0">,</span> <span class="st0">&quot;N_CONSUMERS&quot;</span><span class="br0">&#41;</span> <span class="co1">// flag -c</span>
  94         pipe <span class="sy0">=</span> make<span class="br0">&#40;</span>chan <span class="kw4">int</span><span class="sy0">,</span> <span class="sy0">*</span>BUFFER_SIZE<span class="br0">&#41;</span>
  95         quit    <span class="sy0">=</span> make<span class="br0">&#40;</span>chan <span class="kw4">int</span><span class="br0">&#41;</span>
  96 <span class="br0">&#41;</span>
  97 &nbsp;
  98 func producer <span class="br0">&#40;</span>id <span class="kw4">int</span><span class="br0">&#41;</span> <span class="br0">&#123;</span>
  99         <span class="kw1">for</span> i <span class="sy0">:=</span> <span class="nu0">0</span><span class="sy0">;</span> i <span class="sy0">&lt;</span> <span class="sy0">*</span>MAX_PRODUCTIONS <span class="sy0">||</span> <span class="sy0">*</span>MAX_PRODUCTIONS <span class="sy0">==</span> <span class="nu0">0</span><span class="sy0">;</span> i<span class="sy0">++</span> <span class="br0">&#123;</span>
 100                 Println<span class="br0">&#40;</span>id<span class="sy0">,</span> <span class="st0">&quot;producing:&quot;</span><span class="sy0">,</span> i <span class="sy0">+</span> id <span class="sy0">*</span> 1e5<span class="br0">&#41;</span>
 101                 send<span class="br0">&#40;</span>pipe<span class="sy0">,</span> i <span class="sy0">+</span> id <span class="sy0">*</span> 1e5<span class="br0">&#41;</span>
 102                 random_sleep<span class="br0">&#40;</span><span class="br0">&#41;</span>
 103         <span class="br0">&#125;</span>
 104         signal<span class="br0">&#40;</span>quit<span class="br0">&#41;</span>
 105 <span class="br0">&#125;</span>
 106 &nbsp;
 107 func consumer <span class="br0">&#40;</span>id <span class="kw4">int</span><span class="br0">&#41;</span> <span class="br0">&#123;</span>
 108         <span class="kw1">for</span> <span class="br0">&#123;</span>
 109                 v <span class="sy0">:=</span> recv<span class="br0">&#40;</span>pipe<span class="br0">&#41;</span>
 110                 <span class="kw1">if</span> closed<span class="br0">&#40;</span>pipe<span class="br0">&#41;</span> <span class="br0">&#123;</span> <span class="co1">// canal fechado?</span>
 111                         <span class="kw2">break</span>
 112                 <span class="br0">&#125;</span>
 113                 Println<span class="br0">&#40;</span><span class="st0">&quot;<span class="es1">\t</span><span class="es1">\t</span><span class="es1">\t</span>&quot;</span><span class="sy0">,</span> id<span class="sy0">,</span> <span class="st0">&quot;consuming:&quot;</span><span class="sy0">,</span> v<span class="br0">&#41;</span>
 114                 random_sleep<span class="br0">&#40;</span><span class="br0">&#41;</span>
 115         <span class="br0">&#125;</span>
 116         signal<span class="br0">&#40;</span>quit<span class="br0">&#41;</span>
 117 <span class="br0">&#125;</span>
 118 &nbsp;
 119 func main <span class="br0">&#40;</span><span class="br0">&#41;</span> <span class="br0">&#123;</span>
 120         flag.<span class="me1">Parse</span><span class="br0">&#40;</span><span class="br0">&#41;</span> <span class="co1">// processa flags</span>
 121         Println<span class="br0">&#40;</span><span class="st0">&quot;BUFFER_SIZE =&quot;</span><span class="sy0">,</span> <span class="sy0">*</span>BUFFER_SIZE<span class="br0">&#41;</span>
 122         Println<span class="br0">&#40;</span><span class="st0">&quot;MAX_SLEEP_TIME =&quot;</span><span class="sy0">,</span> <span class="sy0">*</span>MAX_SLEEP_TIME<span class="br0">&#41;</span>
 123         Println<span class="br0">&#40;</span><span class="st0">&quot;MAX_PRODUCTIONS =&quot;</span><span class="sy0">,</span> <span class="sy0">*</span>MAX_PRODUCTIONS<span class="br0">&#41;</span>
 124         Println<span class="br0">&#40;</span><span class="st0">&quot;N_PRODUCERS =&quot;</span><span class="sy0">,</span> <span class="sy0">*</span>N_PRODUCERS<span class="br0">&#41;</span>
 125         Println<span class="br0">&#40;</span><span class="st0">&quot;N_CONSUMERS =&quot;</span><span class="sy0">,</span> <span class="sy0">*</span>N_CONSUMERS<span class="br0">&#41;</span>
 126         <span class="kw1">for</span> i <span class="sy0">:=</span> <span class="nu0">0</span><span class="sy0">;</span> i <span class="sy0">&lt;</span> <span class="sy0">*</span>N_PRODUCERS<span class="sy0">;</span> i<span class="sy0">++</span> <span class="br0">&#123;</span> <span class="co1">// cria produtores</span>
 127                 go producer<span class="br0">&#40;</span>i <span class="sy0">+</span> 1<span class="br0">&#41;</span>
 128         <span class="br0">&#125;</span>
 129         <span class="kw1">for</span> i <span class="sy0">:=</span> <span class="nu0">0</span><span class="sy0">;</span> i <span class="sy0">&lt;</span> <span class="sy0">*</span>N_CONSUMERS<span class="sy0">;</span> i<span class="sy0">++</span> <span class="br0">&#123;</span> <span class="co1">// cria consumidores</span>
 130                 go consumer<span class="br0">&#40;</span>i <span class="sy0">+</span> 1<span class="br0">&#41;</span>
 131         <span class="br0">&#125;</span>
 132         <span class="kw1">for</span> i <span class="sy0">:=</span> <span class="nu0">0</span><span class="sy0">;</span> i <span class="sy0">&lt;</span> <span class="sy0">*</span>N_PRODUCERS<span class="sy0">;</span> i<span class="sy0">++</span> <span class="br0">&#123;</span> <span class="co1">// espera o término dos produtores</span>
 133                 wait<span class="br0">&#40;</span>quit<span class="br0">&#41;</span>
 134         <span class="br0">&#125;</span>
 135         close<span class="br0">&#40;</span>pipe<span class="br0">&#41;</span>   <span class="co1">// fecha comunicação</span>
 136         <span class="kw1">for</span> i <span class="sy0">:=</span> <span class="nu0">0</span><span class="sy0">;</span> i <span class="sy0">&lt;</span> <span class="sy0">*</span>N_CONSUMERS<span class="sy0">;</span> i<span class="sy0">++</span> <span class="br0">&#123;</span>    <span class="co1">// espera o término dos consumidores</span>
 137                 wait<span class="br0">&#40;</span>quit<span class="br0">&#41;</span>
 138         <span class="br0">&#125;</span>
 139 <span class="br0">&#125;</span></pre>
 140 </dd></dl>
 141 <div class="plugin_uparrow">
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 147 </div>
 148 <!-- SECTION "Examples" [83-] -->