C std :: unordered_set SIGFPE异常
作者：互联网
我写了一个程序,我很开心我已经运行了几十次 – 我甚至写下了多次执行的结果 – 现在它不起作用.
你可能会认为我说风筝很高,或者我可能只是改变了一些线条,但我真的不记得在程序上做了任何改动.
根据输入,问题是SIGFPE,它在程序的不同执行中升起.虽然在std :: unordered_set< Point< T>中插入值时引发了信号但是发生了. *取代.
这是我执行此类插入的代码片段：
std::vector<Point<T> *> _point, _centroid;
std::vector<std::unordered_set<Point<T> *> > _cluster;
// Main procedure -- pseudocode
for (point in _point) {
cluster_id = centroid_with_min_distance(point, _centroid);
has_changed = _change_cluster(point, cluster_id);
}
// Changes from one "point->_cluster's unordered_set" to "c's unordered_set"
bool _change_cluster(Point<T> *point, const unsigned int& c) {
if ((point->_cluster == c) &&
(_cluster[c].find(point) != _cluster[c].end())) {
return false;
}
_cluster[point->_cluster].erase(point);
_cluster[c].insert(point); // Insertion that raises the SIGFPE exception
point->_cluster = c;
return true;
}
这是valgrind输出的一个重要部分：
==17636== Invalid read of size 8
==17636== at 0x40A758: std::pair<std::__detail::_Hashtable_iterator<
Point<unsigned int>*, true, false>, bool>
std::_Hashtable<Point<unsigned int>*, Point<unsigned int>*,
std::allocator<Point<unsigned int>*>,
std::_Identity<Point<unsigned int>*>,
std::equal_to<Point<unsigned int>*>,
std::hash<Point<unsigned int>*>,
std::__detail::_Mod_range_hashing,
std::__detail::_Default_ranged_hash,
std::__detail::_Prime_rehash_policy, false, true, true>::
_M_insert<Point<unsigned int>* const&>(
Point<unsigned int>* const&&&,
std::integral_constant<bool, true>) (hashtable.h:966)
==17636== by 0x408EDA: std::_Hashtable<Point<unsigned int>*,
Point<unsigned int>*, std::allocator<Point<unsigned int>*>,
std::_Identity<Point<unsigned int>*>,
std::equal_to<Point<unsigned int>*>,
std::hash<Point<unsigned int>*>,
std::__detail::_Mod_range_hashing,
std::__detail::_Default_ranged_hash,
std::__detail::_Prime_rehash_policy, false, true, true>::
insert(Point<unsigned int>* const&) (hashtable.h:400)
==17636== ... (calls from my program) ...
==17636== Address 0x620a028 is not stack'd, malloc'd or (recently) free'd
==17636==
==17636==
==17636== Process terminating with default action of signal 8 (SIGFPE)
==17636== Integer divide by zero at address 0x402D07D7C
==17636== at 0x40252F: std::__detail::_Mod_range_hashing::operator()(
unsigned long, unsigned long) const (hashtable_policy.h:376)
==17636== by 0x40A66C: std::__detail::_Hash_code_base<Point<unsigned int>*,
Point<unsigned int>*, std::_Identity<Point<unsigned int>*>,
std::equal_to<Point<unsigned int>*>,
std::hash<Point<unsigned int>*>,
std::__detail::_Mod_range_hashing,
std::__detail::_Default_ranged_hash, false>::_M_bucket_index(
Point<unsigned int>* const&, unsigned long,
unsigned long) const (hashtable_policy.h:758)
==17636== by 0x40A772: std::pair<std::__detail::_Hashtable_iterator<
Point<unsigned int>*, true, false>, bool>
std::_Hashtable<Point<unsigned int>*, Point<unsigned int>*,
std::allocator<Point<unsigned int>*>,
std::_Identity<Point<unsigned int>*>,
std::equal_to<Point<unsigned int>*>,
std::hash<Point<unsigned int>*>,
std::__detail::_Mod_range_hashing,
std::__detail::_Default_ranged_hash,
std::__detail::_Prime_rehash_policy, false, true, true>::
_M_insert<Point<unsigned int>* const&>(
Point<unsigned int>* const&&&,
std::integral_constant<bool, true>) (hashtable.h:966)
==17636== by 0x408EDA: std::_Hashtable<Point<unsigned int>*,
Point<unsigned int>*, std::allocator<Point<unsigned int>*>,
std::_Identity<Point<unsigned int>*>,
std::equal_to<Point<unsigned int>*>,
std::hash<Point<unsigned int>*>,
std::__detail::_Mod_range_hashing,
std::__detail::_Default_ranged_hash,
std::__detail::_Prime_rehash_policy, false, true, true>::
insert(Point<unsigned int>* const&) (hashtable.h:400)
==17636== ... (calls from my program) ...
这里的问题是：因为我在我的程序中有计算可能导致除以零 – 它们与此过程没有直接关系 – 但是,错误是否可能被插入阴影？或者我应该在std :: unordered_set< T>？中插入指针时做一些额外的处理？
我正在编译x86_64 GNU / Linux下的程序,我正在使用g(Ubuntu / Linaro 4.6.3-1ubuntu5)4.6.3.
解决方法:
我怀疑’c’超出了_cluster的范围.你能用_cluster.at(c)替换所有的_cluster [c],看它是否发现超出范围的错误.
valgrind输出表明它是无效读取,后跟整数模数误差.由于它正在执行hash_code％bucket_count,我怀疑你访问了向量的范围.
顺便说一句,命名以_开头的东西可能有风险,就像它在全局命名空间中一样,它在技术上保留用于实现.
标签：unordered-set,c,stl,sigfpe 来源： https://codeday.me/bug/20190901/1782094.html