Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>The solution is this, but with drawback that custom defined iterator classes must have typedefs defined inside the classes and not just specialized std::iterator_traits class.</p> <pre><code>// IsIterator.cpp : Defines the entry point for the console application. // #include "stdafx.h" #include &lt;iterator&gt; #include &lt;iostream&gt; #include &lt;vector&gt; template &lt;typename T&gt; class ExtractType { public: typedef T Result; }; template &lt;typename U&gt; class ExtractType&lt;std::iterator_traits&lt;U&gt; &gt; { public: typedef U Result; }; template &lt;typename T&gt; class IsIteratorPointer { public: static const bool value = false; }; template &lt;typename T&gt; class IsIteratorPointer&lt;T*&gt; { public: static const bool value = true; }; template &lt;typename T&gt; class IsIteratorPointer&lt;const T*&gt; { public: static const bool value = true; }; template &lt;typename T&gt; class IsIterator { public: struct TrueValue { char val; }; struct FalseValue { char val[2]; }; template &lt;typename U&gt; static TrueValue evaluateIsIter(typename U::iterator_category*); template &lt;typename U&gt; static FalseValue evaluateIsIter(...); typedef typename ExtractType&lt;T&gt;::Result TestType; static const bool value = IsIteratorPointer&lt;TestType&gt;::value || sizeof(evaluateIsIter&lt;TestType&gt;(0)) == sizeof(TrueValue); }; struct Foo { }; template &lt;&gt; struct std::iterator_traits&lt;Foo&gt; { typedef random_access_iterator_tag iterator_category; }; int _tmain(int argc, _TCHAR* argv[]) { std::cout &lt;&lt; IsIterator&lt; int &gt;::value &lt;&lt; std::endl; std::cout &lt;&lt; IsIterator&lt; std::iterator_traits&lt;int&gt; &gt;::value &lt;&lt; std::endl; std::cout &lt;&lt; IsIterator&lt; std::iterator_traits&lt;int*&gt; &gt;::value &lt;&lt; std::endl; std::cout &lt;&lt; IsIterator&lt; std::iterator_traits&lt;Foo&gt; &gt;::value &lt;&lt; std::endl; // Will be 0 (only drawback) - typedef must be in Foo directly std::cout &lt;&lt; IsIterator&lt; std::vector&lt;int&gt;::const_iterator &gt;::value &lt;&lt; std::endl; return 0; } </code></pre> <p>The question now remains: Can this drawback somehow be removed?</p>
    singulars
    1. This table or related slice is empty.
    1. POHow to know whether std::iterator_traits<T>::value_type is defined
      singulars
      1. PTQuestion
    1. PTAnswer
    1. This table or related slice is empty.
    1. USPavel Celba
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload