Databases
StackOverflow2013
Postsdbo
POType not found when derived from template base class
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POType not found when derived from template base class
    primarykey
    data
    text
    <p>I'm having difficulty understanding why there is a difference in the following two pieces of code, what exactly is the compiler doing.</p> <p>I have the following bit of trivial code, that compiles without any problems as expected:</p> <pre><code>class base { public: typedef int booboo; }; class derived : public base { public: int boo() { booboo bb = 1; return bb; } }; int main() { derived d; d.boo(); return 0; } </code></pre> <p>I take the code from above and add some template parameters, and begin to get errors relating the type booboo not being valid:</p> <pre><code>template &lt;typename T&gt; class base { public: typedef T booboo; }; template &lt;typename T&gt; class derived : public base&lt;T&gt; { public: //typedef typename base&lt;T&gt;::booboo booboo; &lt;-- fixes the problem booboo boo() { booboo bb = T(1); return bb; } }; int main() { derived&lt;int&gt; d; d.boo(); return 0; } </code></pre> <p>Error:</p> <pre><code>prog.cpp:13:4: error: ‘booboo’ does not name a type prog.cpp:13:4: note: (perhaps ‘typename base&lt;T&gt;::booboo’ was intended) prog.cpp: In function ‘int main()’: prog.cpp:23:6: error: ‘class derived&lt;int&gt;’ has no member named ‘boo’ </code></pre> <p><a href="http://ideone.com/jGKYIC" rel="nofollow">http://ideone.com/jGKYIC</a></p> <p>.</p> <p>I would like to understand in details, how a typical c++ compiler goes about compiling the template version of the code, how it differs from compiling the original example, is this an issue to do with multiple passes of the code, and type dependent look-ups?</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USSami Kenjat
    1. USSami Kenjat
    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. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POType not found when derived from template base class
      1. USSami Kenjat
      1. VTFavorite
    1. COIt's always worthwhile posting the errors you got as part of your question.
      singulars
      1. POType not found when derived from template base class
      1. USJBentley
    2. CO@JBentley : Sorry update that, I'll update the question now.
      singulars
      1. POType not found when derived from template base class
      1. USSami Kenjat
 

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