Databases
StackOverflow2013
Postsdbo
POUnusual calling of destructor
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POUnusual calling of destructor
    primarykey
    data
    text
    <p>I am having a strange problem instantiating a structure living inside a class, where in construction it calls the destructor (several times) and even calls the parent object destructor.</p> <p>Class with structure:</p> <pre><code>class Model { public: struct StepModelIO { StepModelIO(Model model, ...) {DoConstruction(Model model, ...);} StepModelIO(const StepModelIO &amp;other) {DoConstruction(Model model, ...); } ~StepModelIO() {} DoConstruction() { ... } } Model(...) { ... } Model(const Model &amp;other) {DoConstruction(...);} ~Model() { ... } private: DoConstruction(...) { } } </code></pre> <p>Calling function:</p> <pre><code>void main() { Model::StepModelIO stepArgs = Model::StepModelIO(...); } </code></pre> <p>The resulting set of calls, with 'object' being the <code>StepModelIO</code> and 'parent' being the <code>Model</code>:</p> <ol> <li>Construct parent w/ copy constructor</li> <li>Construct object</li> <li>Destruct parent</li> <li>Construct object w/ copy constructor</li> <li>Construct parent w/ copy constructor</li> <li>Construct object</li> <li>Destruct parent</li> <li>Destruct object</li> <li>Destruct object (again...)</li> <li>Destruct parent</li> </ol> <p>Unsurprisingly the resulting structure (a <code>StepModelIO</code>) is not in a good state after this all happens, and the path seemed ridiculous. I have the structure housed like this to use the same generic at the parent Model object, which may explain some of the issues.</p> <p>I have tried (perhaps naively) to use the 'rule of three' on constructors and destructors, it's possible I've munged this up badly.</p> <p><strong>Edit:</strong> Full code</p> <pre><code>template&lt;typename U, typename V&gt; class Model{ public: struct StepModelIO { Model&lt;U, V&gt; model; U u; V v; StepModelIO() {} StepModelIO(Model&lt;U, V&gt; model, U u, V v) { this-&gt;model = model; this-&gt;u = u; this-&gt;v = v; } StepModelIO (const StepModelIO &amp;other) { StepModelIO(other.model, other.u, other.v); } ~StepModelIO() { } }; Model(char * libraryPath) {DoConstruction(libraryPath);} Model() {} Model (const Model &amp;other) { DoConstruction(other.m_LibraryPath); } ~Model() { this-&gt;Stop(); } void Init() { if (!this-&gt;m_Initialised) { this-&gt;ModelInit(); m_Initialised = true; } } void Stop() { if (this-&gt;m_Initialised) { this-&gt;ModelStop(); m_Initialised = false; } } void Restart() { this-&gt;ModelRestart(); } void Step(U u, V v) { ModelStep(u, v); } private: char* m_LibraryPath; HINSTANCE m_ModelDLL; bool m_Initialised; typedef int (__cdecl * EmptyModelFunctionPointer)(); // Interpret integer as C code pointer named 'EmptyModelFunctionPointer' typedef int (__cdecl * ModelFunctionPointer)(U u, V v); EmptyModelFunctionPointer ModelInit; EmptyModelFunctionPointer ModelStop; EmptyModelFunctionPointer ModelRestart; ModelFunctionPointer ModelStep; virtual void DoConstruction(char * libraryPath){ this-&gt;m_Initialised = false; this-&gt;m_LibraryPath = libraryPath; this-&gt;m_ModelDLL = LoadLibrary(libraryPath); this-&gt;ModelInit = GetFunction&lt;EmptyModelFunctionPointer&gt;(m_ModelDLL, "Init"); this-&gt;ModelStop = GetFunction&lt;EmptyModelFunctionPointer&gt;(m_ModelDLL, "Stop"); this-&gt;ModelRestart = GetFunction&lt;EmptyModelFunctionPointer&gt;(m_ModelDLL, "Restart"); this-&gt;ModelStep = GetFunction&lt;ModelFunctionPointer&gt;(m_ModelDLL, "Step"); } template&lt;typename pointerType&gt; pointerType GetFunction(HINSTANCE modelLibrary, char * functionName){ return (pointerType)GetProcAddress(HMODULE (modelLibrary),functionName); } }; </code></pre> <p>Caller:</p> <pre><code>StepModelIO&lt;Type_1*, Type_2*&gt; stepArgs = StepModelIO&lt;Type_1*, Type_2*&gt;(newModel, &amp;a, &amp;b[0]); </code></pre>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USJ Collins
    1. USJ Collins
    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
    2. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. CODid you check with a debugger? Sounds like you may corrupt the stack in your initalisation, but since you posted no real code, this is just guessing from the crystal ball.
      singulars
      1. POUnusual calling of destructor
      1. USDevolus
    2. COThe declaration you show in the `main` function does *not* create an instance of the "parent" class. If it does, then you're doing something you're not showing us. Please make a [short and self contained example](http://sscce.org/) showing the problem.
      singulars
      1. POUnusual calling of destructor
      1. USSome programmer dude
    3. COCode you posted does not show any problem. Are there any temporary local object instances inside constructors? Are there member pointers?
      singulars
      1. POUnusual calling of destructor
      1. USmas.morozov
 

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