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POUndefined reference to static member function of Singleton class
 

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  1. POUndefined reference to static member function of Singleton class
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    <p>I implement Singleton class for logging. I declare static of <code>logging_instance_</code> for create only one instance on class name <code>support_service::logging_service</code>. Service_logging call instance of class <code>support_service::logging_service</code> which declear static variable <code>::logging_instance_</code> but show an error</p> <p><code>undefined reference to `support_service::logging_service&lt;std::basic_string&lt;char, std::char_traits&lt;char&gt;, std::allocator&lt;char&gt; &gt;, int&gt;::logging_service()' collect2: ld returned 1 exit status</code> </p> <p><strong>support_service.hpp</strong></p> <pre><code>namespace support_service { template&lt;typename PATH = std::string , typename LEVEL = int&gt; class logging_service { public: static boost::shared_ptr&lt;logging_service&lt;PATH,LEVEL&gt; &gt; instance(); .... private: logging_service(); logging_service(const logging_service&lt;PATH,LEVEL&gt;&amp;); static boost::shared_ptr&lt;logging_service&lt;PATH,LEVEL&gt; &gt; logging_instance_; }; } template&lt;typename PATH, typename LEVEL&gt; boost::shared_ptr&lt;logging_service&lt;PATH,LEVEL&gt; &gt; logging_service&lt;PATH,LEVEL&gt;::instance() { if(logging_instance_.get() == NULL) logging_instance_ = boost::shared_ptr&lt;logging_service&lt;PATH,LEVEL&gt; &gt;(new logging_service&lt;PATH,LEVEL&gt;``()); return logging_instance_; } </code></pre> <p><strong>service_logging.hpp</strong></p> <pre><code>using namespace support_service; template&lt;typename PATH, typename LEVEL&gt; boost::shared_ptr&lt;logging_service&lt;PATH,LEVEL&gt; &gt;support_service::logging_service&lt;PATH,LEVEL&gt;::logging_instance_; namespace service_logging { template&lt;typename PATH = std::string, typename LEVEL = int&gt; class service_logging { public: service_logging(); bool set_logging(PATH file_path); }; } template&lt;typename PATH, typename LEVEL&gt; bool service_logging&lt;PATH,LEVEL&gt;::set_logging(PATH file_path) { boost::shared_ptr&lt;logging_service&lt;PATH,LEVEL&gt; &gt; logging_ = logging_service&lt;PATH,LEVEL&gt;::instance(); ... } </code></pre>
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    1. USR.Chatsiri
    1. USR.Chatsiri
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    1. COCan't you format your code properly? Don't you see how badly it is?
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      1. POUndefined reference to static member function of Singleton class
      1. USNawaz
    2. COAlso, use Singletons -> no sympathy.
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      1. USPuppy
 

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