runtime error <vector>

[mickey]

HI, I have a SLOT

slot() {
vector <QWidget*> tabs;
vector<QSpinBox*> sbx;
vector<QSpinBox*> sby;
vector<QSpinBox*> sbz;
 
cout << "problem \n";
tabs.push_back(tab0); 
tabs.push_back(tab1);
tabs.push_back(tab2);
tabs.push_back(tab3);
tabs.push_back(tab4);
tabs.push_back(tab5);
tabs.push_back(tab6);
tabs.push_back(tab7);
cout << " END problem \n";
}

slot() {
vector <QWidget*> tabs;
vector<QSpinBox*> sbx;
vector<QSpinBox*> sby;
vector<QSpinBox*> sbz;

cout << "problem \n";
tabs.push_back(tab0); 
tabs.push_back(tab1);
tabs.push_back(tab2);
tabs.push_back(tab3);
tabs.push_back(tab4);
tabs.push_back(tab5);
tabs.push_back(tab6);
tabs.push_back(tab7);
cout << " END problem \n";
}

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this slot can be called many time; it happen that the 3th or 4th time, generate a bug error;
"cout << " END problem \n";" isn't print..........do anyone know why??? thanks

[jacek]

Try cerr instead of cout.

[mickey]

sorry wich aim? cerr << "problem "; print exactly the same thing; could you explain me waht you want say?.... ( I knnow at the end of slot() the vector are destroyed.......); the error is a memory read/write error
thanks

[jacek]

the error is a memory read/write error

I understood that it doesn't print "END problem". Post the exact error message.

[mickey]

nothing error in console; my windows isn't english so I try to traslate you:
1. appear a first message that ask if you want send the problem to microsoft (without specify kind of problem)
2. one message that say:

the istruction "0x7c92103c" has referred to memory at "0x000801b3". The memory couldn't be "written". Click on "ok" to close application

I'm sorry the problem isn't there: I comment all slot() and now I can call it 5 times, after same error; do anyone suggest me what it can be? Or how do I can find it? thanks

[jacek]

Or how do I can find it?

Run you application from a debugger and see the stack trace --- it should show you where the problem is.

[mickey]

Right?

vector <GLfloat*> ppp;
  for (int g=0; g < ....; g++) {
      GLfloat* position = new GLfloat[4];
      for (int i=0; i<4; i++) {
            position[i] = ch.toInt(); // split a string as "1543"   
   }
    ppp.push_back(position);
   }
 
  for( std::vector<GLfloat*>::iterator i = ppp.begin(); i != ppp.end(); ++i ) {
    delete [] *i;
   }    
   ppp.clear();

vector <GLfloat*> ppp;
  for (int g=0; g < ....; g++) {
      GLfloat* position = new GLfloat[4];
      for (int i=0; i<4; i++) {
            position[i] = ch.toInt(); // split a string as "1543"   
   }
    ppp.push_back(position);
   }
   
  for( std::vector<GLfloat*>::iterator i = ppp.begin(); i != ppp.end(); ++i ) {
    delete [] *i;
   }    
   ppp.clear();

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and how obtain value of fist element array of first element vector?? thanks

hi; the problem seems the delete for of this vector; if I comment it, it don't crash; is there anything wrong ? thanks

[helcaraxe]

Hej,

You're right, this is the problem.
Try "i++" instead of "++i" in line 10.

If you use ++i, the value in i will be incremented before the body of the loop is executed, leading to a delete with invalid parameter. In fact it is the "*i" in the last call that causes the crash (it is always the last one ).

You could in those cases increment the iterator in the body of the loop, then you have absolute control what happens why. This is for paranoids - like me

Jan

[jacek]

If you use ++i, the value in i will be incremented before the body of the loop is executed

No, it won't.

[helcaraxe]

Then the problem is not in this code snippet

[jacek]

Then the problem is not in this code snippet

Yes, that's why a stack trace is necessary. The memory might be deleted twice or accessed after it was deallocated.