Qt在0x0处读取acces违规，标志= 0x0(第一次机会) [英] Qt read acces violation at:0x0, flags=0x0 (first chance)

问题描述

我有一段非常简单的代码，如下所示:

I have a very simple piece of code as follows:

Letter* Vakje::geefLetter() const
{
    return m_letter;
}

Vakje类使用m_letter的NULL指针初始化，但是我仍然收到读取访问冲突错误，有人可以帮忙吗?

The class Vakje gets initialized with a NULL-pointer for m_letter, but I'm still getting a read access violation error, could someone please help?

这是调用该函数的代码:

this is the code that calls the function:

bool Spelbord::positionIsEmpty(int rij, int kolom) { 
    if (vakjes[rij][kolom]->geefLetter()==nullptr) return true;
    else return false; 
}

推荐答案

如果vakjes[rij][kolom]是NULL，则尝试取消引用指针->会导致未定义的行为(通常是崩溃).

If vakjes[rij][kolom] is NULL, then trying to dereference that pointer -> results in undefined behavior (usually: crash).

只需将代码更改为:

bool Spelbord::positionIsEmpty(int rij, int kolom) { 
  if (vakjes[rij][kolom] == nullptr) return true;
  if (vakjes[rij][kolom]->geefLetter()==nullptr) return true; 

  return false; 
}

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