C ++ CRT检测到VS：社区 [英] C++ CRT detected VS:community

问题描述

你好。我得到了我的班级错误。出于某种原因， VS：社区2017 给了我一个错误。

Hello there. I got my class Error. For some reason VS:Community 2017 gives me an error.

HEAP CORRUPTION DETECTED: after Normal block (#149) at 0x00000282A99E0DE0.
CRT detected that the application wrote to memory after end of heap buffer

我试图改变我的代码尽我所能，我看不出是什么导致了这个问题。



这是我的代码。

Error.h

I've tried to change my code as much as I could and I can't see what's causing the problem.

Here's my code.
Error.h

// compilation safegaurds
#ifndef ICT_ERROR_H_
#define	ICT_ERROR_H_

#include <iostream>
namespace ict {
   class Error {
      char* m_message;
   public:
   // constructors
	   //Sets the m_message member variable to nullptr.
	   Error();
	   //Sets the m_message member variable to nullptr and then uses the message() setter member function to set the error message to the errorMessage argument.
	   Error(const char* errorMessage);
	   //A deleted copy constructor to prevent an Error object to be copied.
	   Error(const Error& em) = delete; //no implementation needed
   // destructor

   // deleted constructor and operator=
	   //A deleted assignment operator overload to prevent an Error object to be assigned to another.
	   Error& operator=(const Error& em) = delete;//no implementation needed
   // operator= for c-style strings
	   void operator=(const char* errorMessage);
   // methods
	   virtual ~Error(){ delete [] m_message; m_message = nullptr;};
	   void clear();
	   bool isClear()const;
	   void message(const char* value);
	   operator const char*() const;
	   operator bool()const;
   // cast overloads
	   friend std::ostream& operator<<(std::ostream& ostr, const Error& em);
   };
   // operator << overload prototype for cout
 
   std::ostream& operator<<(std::ostream& ostr, const Error& em);
}
#endif //ICT_ERROR_H_

Error.cpp

Error.cpp

#define _CRT_SECURE_NO_WARNINGS 

#include "Error.h"
#include <iostream>
#include <cstring>

namespace ict{
	Error::Error() {
		m_message = nullptr;
	}

	Error::Error(const char* errorMessage) {
		m_message = nullptr;
		message(errorMessage);
	}

	//have a look
	void Error::operator=(const char* errorMessage) {
		clear();//dealloc m_message
		message(errorMessage);
	}

	void Error::clear() {
		delete[] m_message;
		m_message = nullptr;

	}


	bool Error::isClear()const {
		bool clear = false;
		if (m_message == nullptr) {
			clear = true;
		}
		return clear;
	}

	void Error::message(const char* value) {
		//clear();//dealloc m_message
		delete[] m_message;
		m_message = new char[strlen(value + 1)];
		strcpy(m_message, value);
	}

	Error::operator const char*() const {
		return m_message;
	}

	Error::operator bool()const {
		return isClear();
	}

	std::ostream& operator<<(std::ostream& ostr, const Error& em) {
		if (em.isClear()) {
			//nothing
		}
		else {
			ostr << em.m_message;
		}

		return ostr;
	}

}//namespace ict

Main.cpp

Main.cpp

#include <iostream>
#include "Error.h"
using namespace std;
using namespace ict;
int main(){
  Error T("Testing Error Message");
  Error e;
  bool ok = true;
  int pc = 1;
  cout << T << endl << e << endl << "isClear(): " << (e.isClear() ? "Passed!" : "failed!") << endl;
  if (!e.isClear()) ok = false;
  for (int i = 0; i < 10000000; i++){
    e = "Some error message that is really long long  long  long  long  long  long  long"
       " long  long  long  long  long  long  long  long  long  long  long  long  long"
       " long  long  long  long  long  long  long  long  long  long  long  long  long"
       " long  long  long  long  long  long  long  long  long  long  long  long  long"
       " long  long  long  long  long  long  long  long  long  long  long  long  long"
       " long  long  long  long  long  long  long  long  long  long  long  long  long"
       ;
    if (i % 100000 == 0) cout << "\r" << pc++ << "%";
  }
  cout << endl << e << endl << "isClear(): " << (e ? "Failed!" : "Passed!") << endl;
  if (e) ok = false;
  e.message("Short Error Message");
  cout << e << " is the same as " << (const char*)e << endl << "isClear(): " << (e.isClear() ? "Failed!" : "Passed!") << endl;
  e.clear();
  cout << "Nothing here: >" << e << "<" << endl << "isClear(): " << (e.isClear() ? "Passed!" : "Failed!") << endl;
  if (!e) ok = false;
  cout << (ok ? "All tests passed!" : "Failed!") << endl;
  return 0;
}

我的尝试：



我试图用g ++在Linux终端中编译相同的代码，它按预期工作！所以，我假设我在某处发生了内存泄漏。有人可以指点我去哪儿吗？



Linux终端输出：

What I have tried:

I've tried to compile the same code in Linux terminal with g++ and it works there as expected! So, I assume I got a memory leak some where. Could someone please point me where to look?

Linux terminal output:

Testing Error Message

isClear(): Passed!
100%
Some error message that is really long long  long  long  long  long  long  long long  long  long  long  long  long  long  long  long  long  long  long  long long  long  long  long  long  long  long  long  long  long  long  long  long long  long  long  long  long  long  long  long  long  long  long  long  long long  long  long  long  long  long  long  long  long  long  long  long  long long  long  long  long  long  long  long  long  long  long  long  long  long
isClear(): Passed!
Short Error Message is the same as Short Error Message
isClear(): Passed!
Nothing here: ><
isClear(): Passed!
All tests passed!

推荐答案

错误在这里：

The error is here:

m_message = new char[strlen(value + 1)];

这将分配两个小于所需的字符（当传递的字符串为空时随机大小）。



必须是：

That will allocate two characters less than required (random size when the passed string is empty).

It must be:

m_message = new char[strlen(value) + 1];

G ++版本中也存在错误但未检测到错误。

The error is also present with G++ builds but not detected.

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