c++ - 内存泄漏 C++

Question

我有一个用 c++ 编写的代码，它在 visual studio 上可以正常工作，但是当我将它转移到 linux (QT Designer) 时，我得到如下所示的运行时错误:

*** glibc detected *** /home/hfarazi/Test/QT/Test-build-desktop/Test: malloc(): memory corruption: 0x082c2c80 ***
======= Backtrace: =========
/lib/i386-linux-gnu/libc.so.6(+0x6ff22)[0x42cf22]
/lib/i386-linux-gnu/libc.so.6(+0x718be)[0x42e8be]
/lib/i386-linux-gnu/libc.so.6(__libc_malloc+0x68)[0x4307f8]
/usr/lib/i386-linux-gnu/libstdc++.so.6(_Znwj+0x27)[0x2c89d7]
/usr/lib/i386-linux-gnu/libstdc++.so.6(_Znaj+0x1b)[0x2c8afb]
/home/hfarazi/Test/QT/Test-build-desktop/Test[0x804abdc]
/home/hfarazi/Test/QT/Test-build-desktop/Test[0x8062860]
/home/hfarazi/Test/QT/Test-build-desktop/Test[0x80644b5]
/home/hfarazi/Test/QT/Test-build-desktop/Test[0x806e449]
/home/hfarazi/Test/QT/Test-build-desktop/Test[0x80604d5]
/home/hfarazi/Test/QT/Test-build-desktop/Test[0x8049205]
/lib/i386-linux-gnu/libc.so.6(__libc_start_main+0xf3)[0x3d6113]
/home/hfarazi/Test/QT/Test-build-desktop/Test[0x8049351]
======= Memory map: ========
00219000-002f7000 r-xp 00000000 07:00 527926     /usr/lib/i386-linux-gnu/libstdc++.so.6.0.16
002f7000-002f8000 ---p 000de000 07:00 527926     /usr/lib/i386-linux-gnu/libstdc++.so.6.0.16
002f8000-002fc000 r--p 000de000 07:00 527926     /usr/lib/i386-linux-gnu/libstdc++.so.6.0.16
002fc000-002fd000 rw-p 000e2000 07:00 527926     /usr/lib/i386-linux-gnu/libstdc++.so.6.0.16
002fd000-00304000 rw-p 00000000 00:00 0 
00339000-00357000 r-xp 00000000 07:00 266017     /lib/i386-linux-gnu/ld-2.13.so
00357000-00358000 r--p 0001d000 07:00 266017     /lib/i386-linux-gnu/ld-2.13.so
00358000-00359000 rw-p 0001e000 07:00 266017     /lib/i386-linux-gnu/ld-2.13.so
003a2000-003b9000 r-xp 00000000 07:00 273114     /lib/i386-linux-gnu/libpthread-2.13.so
003b9000-003ba000 r--p 00016000 07:00 273114     /lib/i386-linux-gnu/libpthread-2.13.so
003ba000-003bb000 rw-p 00017000 07:00 273114     /lib/i386-linux-gnu/libpthread-2.13.so
003bb000-003bd000 rw-p 00000000 00:00 0 
003bd000-00535000 r-xp 00000000 07:00 273100     /lib/i386-linux-gnu/libc-2.13.so
00535000-00537000 r--p 00178000 07:00 273100     /lib/i386-linux-gnu/libc-2.13.so
00537000-00538000 rw-p 0017a000 07:00 273100     /lib/i386-linux-gnu/libc-2.13.so
00538000-0053b000 rw-p 00000000 00:00 0 
00777000-0079f000 r-xp 00000000 07:00 273104     /lib/i386-linux-gnu/libm-2.13.so
0079f000-007a0000 r--p 00028000 07:00 273104     /lib/i386-linux-gnu/libm-2.13.so
007a0000-007a1000 rw-p 00029000 07:00 273104     /lib/i386-linux-gnu/libm-2.13.so
00bf7000-00bf8000 r-xp 00000000 00:00 0          [vdso]
00df3000-00e0f000 r-xp 00000000 07:00 262077     /lib/i386-linux-gnu/libgcc_s.so.1
00e0f000-00e10000 r--p 0001b000 07:00 262077     /lib/i386-linux-gnu/libgcc_s.so.1
00e10000-00e11000 rw-p 0001c000 07:00 262077     /lib/i386-linux-gnu/libgcc_s.so.1
08048000-08075000 r-xp 00000000 07:00 401931     /home/hfarazi/Test/QT/Test-build-desktop/Test
08075000-08076000 r--p 0002c000 07:00 401931     /home/hfarazi/Test/QT/Test-build-desktop/Test
08076000-08077000 rw-p 0002d000 07:00 401931     /home/hfarazi/Test/QT/Test-build-desktop/Test
082ba000-082db000 rw-p 00000000 00:00 0          [heap]
b7600000-b7621000 rw-p 00000000 00:00 0 
b7621000-b7700000 ---p 00000000 00:00 0 
b77f4000-b77f8000 rw-p 00000000 00:00 0 
b780a000-b780d000 rw-p 00000000 00:00 0 
bff44000-bff65000 rw-p 00000000 00:00 0          [stack]

你能帮我找出错误吗!由于这是一个公司项目，我无法轻易发送代码。提前谢谢。

---

我认为问题出在这个类中，一个想法？

#define NOT_VALID NULL
#define STACK_INITIAL_ALLOC   10
#define STACK_CHUNK_ALLOC    10
template<class T>
class stack
{
public:
    stack()
        : value(0), length(0), allocated(0)
        { }

    stack(const T &value)
        : value(0), length(0), allocated(0)
        {
            push(value);
        }

    ~stack()
        {
            if (value)
                delete [] value;
        }

    void push(const T &_value)
        {
            if (length == allocated)
                allocate();  // Allocate more memory

            value[length++] = _value;
        }

    T &pop()
        {
            if (length > 0)
            {   
                //shrink();
                length--;
                return value[length];
            }
        }

    T &peak()
        {
            if (length > 0)
                return value[length - 1];
            //else
               // throw runtime_error("stack empty");
        }

    // Return the number of length in the stack
    size_t count() const
        {
            return length;
        }

    size_t get_allocated() const
        {
            return allocated;
        }

private:
    T      *value;      // The actual stack
    size_t  length;   // Number of length in stack
    size_t  allocated; // Allocated length in stack

    void copy(T *from, T *to)
        {
            for (size_t i = 0; i < length; i++)
                *to++ = *from++;
        }

    void allocate()
        {
            if (value == 0)
            {
                allocated = STACK_INITIAL_ALLOC;
                value = new T[allocated];
            }
            else
            {
                // We need to allocate more memory

                size_t new_allocated = allocated + STACK_CHUNK_ALLOC;
                T *new_value = new T[new_allocated];

                // Copy from old stack to new stack
                copy(value, new_value);

                // Delete the old value
                delete [] value;

                allocated = new_allocated;
                value = new_value;
            }
        }

    // Shrink the stack, if lots of it is unused
    void shrink()
        {
            // The limit which the number of length must be lower than
            size_t shrink_limit = allocated - STACK_CHUNK_ALLOC * 2;

            // Do not shrink if we will get lower than the initial allocation (shrink_limit > STACK_INITIAL_ALLOC)
            if (shrink_limit > STACK_INITIAL_ALLOC && length < shrink_limit)
            {
                // We can shrink the allocated memory a little
                size_t new_allocated = allocated - STACK_CHUNK_ALLOC;

                T *new_value = new T[new_allocated];

                copy(value, new_value);

                delete [] value;

                value = new_value;
                allocated = new_allocated;
            }
        }
};

Answer 1

如果您不处理线程，那么当您以某种方式读取/写入数组边界时，很可能会出现此类问题。

由于这种操作的结果是未定义的，因此在某些特定的主机/编译器中可能看不到问题，并且只有当您将代码传输到另一个主机时才会发生。

如果你的程序很大，有时候这类问题真的很难搞清楚。

除了使用调试器之外，还有一个建议是删除部分代码(如果可能)并尝试缩小问题的来源范围。