Question

我的二进制文件正在崩溃。在运行核心转储时，我发现了以下内容：

#0  0x00a6a363 in memmove () from /lib/tls/libc.so.6
(gdb) frame 1
#1  0x083a108c in std::__copy_trivial<piola::piolaOrderBook*> (__first=0xb277f2c4, __last=0xb277f2bc, __result=0xb277f2c0)
    at /usr/lib/gcc/i386-redhat-linux/3.4.6/../../../../include/c++/3.4.6/bits/stl_algobase.h:258
258           std::memmove(__result, __first, sizeof(_Tp) * (__last - __first));
(gdb) frame 2
#2  0x083a0ad6 in std::__copy_aux2<piola::piolaOrderBook*> (__first=0xb277f2c4, __last=0xb277f2bc, __result=0xb277f2c0)
    at /usr/lib/gcc/i386-redhat-linux/3.4.6/../../../../include/c++/3.4.6/bits/stl_algobase.h:279
279         { return std::__copy_trivial(__first, __last, __result); }
(gdb) frame 3
#3  0x083a02d1 in std::__copy_ni2<piola::piolaOrderBook**, __gnu_cxx::__normal_iterator<piola::piolaOrderBook**, std::vector<piola::piolaOrderBook*, std::allocator<emapi::EmapiOrderBook*> > > > (__first=0xb277f2c4, __last=0xb277f2bc, __result=
      {_M_current = 0xb277f2c0})
    at /usr/lib/gcc/i386-redhat-linux/3.4.6/../../../../include/c++/3.4.6/bits/stl_algobase.h:296
296           return _OutputIterator(std::__copy_aux2(__first, __last, __result.base(),
(gdb) frame 4
#4  0x0839f1b0 in std::__copy_ni1<__gnu_cxx::__normal_iterator<piola::piolaOrderBook**, std::vector<piola::piolaOrderBook*, std::allocator<piola::piolaOrderBook*> > >, __gnu_cxx::__normal_iterator<piola::piolaOrderBook**, std::vector<piola::piolaOrderBook*, std::allocator<piola::piolaOrderBook*> > > > (__first={_M_current = 0xb277f2c4}, __last=
      {_M_current = 0xb277f2bc}, __result={_M_current = 0xb277f2c0})
    at /usr/lib/gcc/i386-redhat-linux/3.4.6/../../../../include/c++/3.4.6/bits/stl_algobase.h:317
317           return std::__copy_ni2(__first.base(), __last.base(),
(gdb) frame 5
#5  0x0839d676 in std::copy<__gnu_cxx::__normal_iterator<piola::piolaOrderBook**, std::vector<piola::piolaOrderBook*, std::allocator<piola::piolaOrderBook*> > >, __gnu_cxx::__normal_iterator<piola::piolaOrderBook**, std::vector<piola::piolaOrderBook*, std::allocator<piola::piolaOrderBook*> > > > (__first={_M_current = 0xb277f2c4}, __last={_M_current = 0xb277f2bc},
    __result={_M_current = 0xb277f2c0})
    at /usr/lib/gcc/i386-redhat-linux/3.4.6/../../../../include/c++/3.4.6/bits/stl_algobase.h:358
358            return std::__copy_ni1(__first, __last, __result, __Normal());
(gdb)

大部分内容对我来说都很神秘，但是在查找memmove时，似乎代码崩溃了，因为它无法处理向量中的删除（因为从向量中删除对于大向量来说是一个非常繁重的操作）？

我说错了吗？如果是，我该如何解决这个问题（除了修复设计之外）？

代码在这里：

for (orderbkIterator = vOrderBook.begin(); orderbkIterator != vOrderBook.end(); orderbkIterator++)
    {

        if (  (*(*orderbkIterator)->getOrderBookId()) == *(TradableInst->getOrderBookId()) )
        {
            long long a = (*(*orderbkIterator)->getOrderBookId());
            ADDVLOG(LOG_INFO, "Removing record (%lld) from vOrderBook", a );
            vOrderBook.erase(orderbkIterator);
        }

Answer 1

来自std::vector::erase()：

对擦除元素及其与容器末尾之间元素的迭代器和引用无效。过去的迭代器也是无效的。

如果orderbkIterator被调用，则下次递增时erase()将无效。更改循环的结构，因为erase()在删除的迭代器之后返回下一个迭代器，这意味着只有在erase()没有发生时才会增加：

for (orderbkIterator = vOrderBook.begin(); orderbkIterator != vOrderBook.end();)
{
    if (...)
    {
        orderbkIterator = vOrderBook.erase(orderbkIterator);
    }
    else
    {
        ++orderbkIterator;
    }
}

Answer 2

我很确定

vOrderBook.erase(orderbkIterator);

将使迭代器无效。继续增加会导致不确定的结果。

Answer 3

删除擦除习惯用法可以防止使用无效迭代器的许多陷阱。

使用这个习惯用法重写循环看起来如下：

vOrderBook.erase(
  std::remove_if(vOrderBook.begin(), vOrderBook.end(), <unary-predicate>),
  vOrderBook.end());

一元谓词可以是lambda或functor。

STL向量的大规模删除导致我的二进制文件崩溃

3 个答案: