C++使用 std::set 并出现分段错误 D:

发布于 2024-12-10 19:36:42 字数 2002 浏览 0 评论 0原文

我不知道 valgrind 中的错误报告告诉我什么......但以下是与该问题相关的代码部分：

template<typename T>
struct CompareEvents {
public:
    bool operator()(const T a, const T b) const {
        return a.time < b.time ? true : false;
    } 
};


class EventManager {
public:
    void EventManager::SendEvent(int delay, size_t sender, size_t receiver, size_t eventId) {
        if (delay > 0) {
            eventQueue.insert(Event((GetTime() + delay), sender, receiver, eventId));  //line 55
        }
    }
private:
    std::set<Event, CompareEvents<Event>> eventQueue;
}

Event 只是一个简单的结构，有四个参数（时间、发送者、接收者和 ID）。

从我的测试类调用 SendEvent 会导致一个可爱的段错误...看起来像这样（valgrind）：

==998== Invalid read of size 8
==998==    at 0x40D544: std::_Rb_tree<Event, Event, std::_Identity<Event>, CompareEvents<Event>, std::allocator<Event> >::_M_begin() (stl_tree.h:493)
==998==    by 0x40D8C4: std::pair<std::_Rb_tree_iterator<Event>, bool> std::_Rb_tree<Event, Event, std::_Identity<Event>, CompareEvents<Event>, std::allocator<Event> >::_M_insert_unique<Event>(Event&&) (stl_tree.h:1261)
==998==    by 0x40C44B: std::__cxx1998::set<Event, CompareEvents<Event>, std::allocator<Event> >::insert(Event&&) (stl_set.h:419)
==998==    by 0x40ADE2: std::__debug::set<Event, CompareEvents<Event>, std::allocator<Event> >::insert(Event&&) (set.h:210)
==998==    by 0x40A130: EventManager::SendEvent(int, unsigned long, unsigned long, unsigned long) (EventManager.cc:55)
==998==    by 0x402D07: main (main.cc:28)
==998==  Address 0x10 is not stack'd, malloc'd or (recently) free'd

嗯...丑陋？ main.cc:28 是我的 SendEvent 调用，一个简单的：（

EventManager::Instance()->DispatchEvent(3, 1, 1, 1);

它是作为单例类构建的，以防您想知道 Instance() 方法）。

这就是我的问题。我无法弄清楚它，但我不知道，我是否把插入到我的 std::set 中搞砸了？我以前没用过套装，所以可能是这样吗？我需要初始化一些东西吗？我很困惑...

原文

I have no clue what my error report in valgrind is telling me... but here are the parts of my code pertinent to the issue:

template<typename T>
struct CompareEvents {
public:
    bool operator()(const T a, const T b) const {
        return a.time < b.time ? true : false;
    } 
};


class EventManager {
public:
    void EventManager::SendEvent(int delay, size_t sender, size_t receiver, size_t eventId) {
        if (delay > 0) {
            eventQueue.insert(Event((GetTime() + delay), sender, receiver, eventId));  //line 55
        }
    }
private:
    std::set<Event, CompareEvents<Event>> eventQueue;
}

Event is just a simple struct which has four parameters (time, sender, receiver and ID).

Calling SendEvent from my test class results in a lovely seg fault... which looks like this (valgrind):

==998== Invalid read of size 8
==998==    at 0x40D544: std::_Rb_tree<Event, Event, std::_Identity<Event>, CompareEvents<Event>, std::allocator<Event> >::_M_begin() (stl_tree.h:493)
==998==    by 0x40D8C4: std::pair<std::_Rb_tree_iterator<Event>, bool> std::_Rb_tree<Event, Event, std::_Identity<Event>, CompareEvents<Event>, std::allocator<Event> >::_M_insert_unique<Event>(Event&&) (stl_tree.h:1261)
==998==    by 0x40C44B: std::__cxx1998::set<Event, CompareEvents<Event>, std::allocator<Event> >::insert(Event&&) (stl_set.h:419)
==998==    by 0x40ADE2: std::__debug::set<Event, CompareEvents<Event>, std::allocator<Event> >::insert(Event&&) (set.h:210)
==998==    by 0x40A130: EventManager::SendEvent(int, unsigned long, unsigned long, unsigned long) (EventManager.cc:55)
==998==    by 0x402D07: main (main.cc:28)
==998==  Address 0x10 is not stack'd, malloc'd or (recently) free'd

Umm... ugly? main.cc:28 is my SendEvent call, a simple:

EventManager::Instance()->DispatchEvent(3, 1, 1, 1);

(It's built as a singleton class, in case you are wondering about the Instance() method).

So that's my problem. I can't make heads or tails of it, but I dunno, am I botching the insert into my std::set? I haven't used sets before, so that might be it? Do I need to initialize something? I'm pretty confused...

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强者自强 2024-12-17 19:36:42

在没有看到更多信息的情况下，这是一个猜测！

我猜测您调用 SendEvent 的 EventManager 是 NULL。 valgrind 错误告诉您 0x10 是 valgrind 不知道的地址，而 0x10 是一个很好的整数，可能是结构中的 16 字节偏移量（ EventManager），但您的指针为NULL。在大多数平台上NULL + 0x10 = 0x10。

这很愚蠢，很容易检查：让程序在 gdb 中出现段错误，跳转到 SendEvent 调用的帧，然后查看 this 是否为<代码>NULL。