Databases
StackOverflow2013
Postsdbo
POGNU GCC (g++): Why does it generate multiple dtors?
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POGNU GCC (g++): Why does it generate multiple dtors?
    primarykey
    data
    text
    <p>Developing environment: GNU GCC (g++) 4.1.2</p> <p>While I'm trying to investigate how to increase 'code coverage - particularly function coverage' in unit testing, I've found that some of class dtor seems to be generated multiple times. Does some of you have any idea on why, please?</p> <p>I tried and observed what I mentioned the above by using the following code.</p> <p>In "test.h"</p> <pre><code>class BaseClass { public: ~BaseClass(); void someMethod(); }; class DerivedClass : public BaseClass { public: virtual ~DerivedClass(); virtual void someMethod(); }; </code></pre> <p>In "test.cpp"</p> <pre><code>#include &lt;iostream&gt; #include "test.h" BaseClass::~BaseClass() { std::cout &lt;&lt; "BaseClass dtor invoked" &lt;&lt; std::endl; } void BaseClass::someMethod() { std::cout &lt;&lt; "Base class method" &lt;&lt; std::endl; } DerivedClass::~DerivedClass() { std::cout &lt;&lt; "DerivedClass dtor invoked" &lt;&lt; std::endl; } void DerivedClass::someMethod() { std::cout &lt;&lt; "Derived class method" &lt;&lt; std::endl; } int main() { BaseClass* b_ptr = new BaseClass; b_ptr-&gt;someMethod(); delete b_ptr; } </code></pre> <p>When I built the above code (g++ test.cpp -o test) and then see what kind of symbols have been generated as follows,</p> <p>nm --demangle test</p> <p>I could see the following output.</p> <pre><code>==== following is partial output ==== 08048816 T DerivedClass::someMethod() 08048922 T DerivedClass::~DerivedClass() 080489aa T DerivedClass::~DerivedClass() 08048a32 T DerivedClass::~DerivedClass() 08048842 T BaseClass::someMethod() 0804886e T BaseClass::~BaseClass() 080488f6 T BaseClass::~BaseClass() </code></pre> <p>My questions are as follows.</p> <p>1) Why multiple dtors have been generated (BaseClass - 2, DerivedClass - 3)?</p> <p>2) What are the difference among these dtors? How those multiple dtors will be selectively used?</p> <p>I now have a feeling that in order to achieve 100% function coverage for C++ project, we would need to understand this so that I can invoke all those dtors in my unit tests.</p> <p>I would greately appreciate if someone could give me the reply on the above.</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USrazlebe
    1. USSmg
    plurals
    1. This table or related slice is empty.
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    3. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POGNU GCC (g++): Why does it generate multiple dtors?
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POGNU GCC (g++): Why does it generate multiple dtors?
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. POGNU GCC (g++): Why does it generate multiple dtors?
      1. This table or related slice is empty.
      1. VTUpMod
    1. CO+1 for including a minimal, complete sample program. (http://sscce.org)
      singulars
      1. POGNU GCC (g++): Why does it generate multiple dtors?
      1. USRobᵩ
    2. CODoes your base class intentionally have a non-virtual destructor?
      singulars
      1. POGNU GCC (g++): Why does it generate multiple dtors?
      1. USKerrek SB
    3. COA small observation; you have sinned, and not made your BaseClass destructor virtual.
      singulars
      1. POGNU GCC (g++): Why does it generate multiple dtors?
      1. USLyke
 

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