Question

for(ItemTemplateListIterator iter = item_template_list.begin(); iter != item_template_list.end(); ++iter) {
    int id = iter->first;
    string description = iter->second->description;
    some_file_stream << id << endl;
    some_file_stream << description << endl;

}

Where item_template_list is a map of <int, MyClass*>, ItemTemplateListIterator is a typedef for a const_iterator of map<int, MyClass*> and MyClass has a public string property called description.

Answer 1

What very likely happened is that the object pointers that you stored in the map are not valid anymore (because the memory was deallocated elsewhere). Attempting to access a deallocated memory area causes a segfault. Not valid is meaning either NULL or having a so-called “dangling pointer“.

Maybe also you are modifying the map or objects in the map in another thread while iterating through it.

There is too little code here for me to help you more.