Jump to content

  • Log In with Google      Sign In   
  • Create Account


Crash in std::set::insert()


Old topic!
Guest, the last post of this topic is over 60 days old and at this point you may not reply in this topic. If you wish to continue this conversation start a new topic.

  • You cannot reply to this topic
10 replies to this topic

#1 lride   Members   -  Reputation: 633

Like
0Likes
Like

Posted 09 December 2012 - 08:34 PM

I made a bomberman-like program. I keep a 2d array of Tile object in a GameMap object.
Every time the player crosses to a different tile, the new tile's onEnter() gets called and the old tile's onExit() gets called
Each tile object has std::set that stores all the entities that are on the tile. onEnter() adds the pointer to the entity to its set and onExit() erases the pointer from its set.
But my game crashes there.

[source lang="cpp"] //Check if the player moved to a different tile if(previousLoc!=currentLoc) { gameWorld->getGameMap().onEnter(currentLoc.x, currentLoc.y, this); gameWorld->getGameMap().onExit(previousLoc.x, previousLoc.y, this); } GameMap::onEnter(int x, int y, Entity * e) { tiles[y][x].onEnter(e); } GameMap::onExit(int x, int y, Entity *e) { tiles[y][x].onExit(e); } Tile::onEnter(Entity * e) { entities.insert(e); //entities is declared as std::set<Entity*> entities } Tile::onExit(Entity * e) { entities.erase(e); } [/source]


The stack trace shows up like this
> Game3.exe!std::_Tree<std::_Tset_traits<Entity *,std::less<Entity *>,std::allocator<Entity *>,0> >::_Root() Line 2139 C++
Game3.exe!std::_Tree<std::_Tset_traits<Entity *,std::less<Entity *>,std::allocator<Entity *>,0> >::_Insert_nohint<Entity * const &,std::_Nil>(bool _Leftish, Entity * const & _Val, std::_Nil _Newnode) Line 1784 C++
Game3.exe!std::_Tree<std::_Tset_traits<Entity *,std::less<Entity *>,std::allocator<Entity *>,0> >::insert(Entity * const & _Val) Line 1304 C++
Game3.exe!std::set<Entity *,std::less<Entity *>,std::allocator<Entity *> >::insert(Entity * const & _Val) Line 166 C++
Game3.exe!Tile::onEnter(Entity * e) Line 17 C++
Game3.exe!GameMap::onEnter(int x, int y, Entity * e) Line 118 C++

What can possibly cause my program to crash?

Edited by lride, 09 December 2012 - 08:34 PM.

An invisible text.

Sponsor:

#2 SiCrane   Moderators   -  Reputation: 9575

Like
0Likes
Like

Posted 09 December 2012 - 09:08 PM

Depending on exactly what type tiles is, some potential causes can include calling onEnter() on an uninitialized pointer, a pointer to a deleted object, a pointer to an unconstructed object, non-kosher memory use like memest() on a non-POD type, buffer overruns, accessing past the end of allocated memory, and so on.

#3 lride   Members   -  Reputation: 633

Like
0Likes
Like

Posted 09 December 2012 - 09:15 PM

onEnter() merely stores the pointer in the set. It doesn't try to dereference the pointer.
An invisible text.

#4 wqking   Members   -  Reputation: 756

Like
0Likes
Like

Posted 09 December 2012 - 09:59 PM

Are you sure tiles[y][x] is valid and x, y are not out of bounds?

http://www.cpgf.org/
cpgf library -- free C++ open source library for reflection, serialization, script binding, callbacks, and meta data for OpenGL Box2D, SFML and Irrlicht.
v1.5.5 was released. Now supports tween and timeline for ease animation.


#5 lride   Members   -  Reputation: 633

Like
0Likes
Like

Posted 09 December 2012 - 10:09 PM

Are you sure tiles[y][x] is valid and x, y are not out of bounds?


Yes, I'm using std::array in debug mode, which should result in assertion failure if x and y is out of bound
An invisible text.

#6 SiCrane   Moderators   -  Reputation: 9575

Like
0Likes
Like

Posted 09 December 2012 - 10:15 PM

onEnter() merely stores the pointer in the set. It doesn't try to dereference the pointer.

I'm not talking about the pointer that you're trying to put in the set, I'm talking about the object that you're calling onEnter() on, either the GameMap or Tile objects.

#7 lride   Members   -  Reputation: 633

Like
0Likes
Like

Posted 09 December 2012 - 10:21 PM


onEnter() merely stores the pointer in the set. It doesn't try to dereference the pointer.

I'm not talking about the pointer that you're trying to put in the set, I'm talking about the object that you're calling onEnter() on, either the GameMap or Tile objects.

anyways uninitialized pointer or pointer to deleted object, or pointer to unconstructed object aren't possible.
I'm passing the pointer with "this" pointer as you can see
An invisible text.

#8 SiCrane   Moderators   -  Reputation: 9575

Like
0Likes
Like

Posted 09 December 2012 - 10:30 PM

1) Using this is no guarantee that the pointer is initialized.
struct Object {
  void func(void) {
    some_other_function(this);
  }
};

Object * obj; // not initialized
obj->func(); // some_other_function() will receive an uninitialized pointer.
2) I'm still not talking about the pointer that you're storing in the set, I'm talking about the object that the member function is being called on, which looks to be whatever gameWorld->getGameMap() returns.

#9 lride   Members   -  Reputation: 633

Like
0Likes
Like

Posted 09 December 2012 - 10:43 PM

Ok I somewhat mitigated the crash.
Originally, all base entity had a protected pointer to the gameWorld object
But now I changed it so that I passed the gameWorld object each time in a loop.

Then I get list out of range assertion failure so at least I know what's wrong
An invisible text.

#10 lride   Members   -  Reputation: 633

Like
0Likes
Like

Posted 09 December 2012 - 11:13 PM

Now I completely solved the problem.
I have no idea why the crash occurred.
I will try to find the complete minimal example that reproduces the problem
An invisible text.

#11 Trienco   Crossbones+   -  Reputation: 2139

Like
2Likes
Like

Posted 10 December 2012 - 11:24 PM

Now I completely solved the problem.
I have no idea why the crash occurred.


Not to rain on your parade, but those two statements are usually mutually exclusive.
f@dzhttp://festini.device-zero.de




Old topic!
Guest, the last post of this topic is over 60 days old and at this point you may not reply in this topic. If you wish to continue this conversation start a new topic.



PARTNERS