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The following container functions can invalidate iterators, references, and pointers under certain circumstances.

 
ClassFunctionIteratorsReferences/PointersNotes
std::deque
    





insert(), emplace_front(), emplace_back(),
emplace(), push_front(), push_back()
XX

An insertion in the middle of the deque invalidates all the iterators and references to elements of the deque. An insertion at either end of the deque invalidates all the iterators to the deque but has no effect on the validity of references to elements of the deque. ([deque.modifiers], paragraph 1)

 


erase(), pop_back(), resize()XX

An erase operation that erases the last element of a deque invalidates only the past-the-end iterator and all iterators and references to the erased elements. An erase operation that erases the first element of a deque but not the last element invalidates only the erased elements. An erase operation that erases neither the first element nor the last element of a deque invalidates the past-the-end iterator and all iterators and references to all the elements of the deque. ([deque.modifiers], paragraph 4)

 


clear()XX

Destroys all elements in the container. Invalidates all references, pointers, and iterators referring to the elements of the container and may invalidate the past-the-end iterator. ([sequence.reqmts], Table 100)

std::forward_list
 
    





erase_after(), pop_front(), resize()XXerase_after shall invalidate only iterators and references to the erased elements. ([forwardlist.modifiers], paragraph 1)
 

remove(), unique()XX

Invalidates only the iterators and references to the erased elements. ([forwardlist.ops], paragraph 12 & paragraph 16)

 


clear()XXDestroys all elements in the container. Invalidates all references, pointers, and iterators referring to the elements of the container and may invalidate the past-the-end iterator. ([sequence.reqmts], Table 100)
std::list
   
  





erase(), pop_front(), pop_back(), clear(), remove(), remove_if(), unique()XXInvalidates only the iterators and references to the erased elements. ([list.modifiers], paragraph 3 and [list.ops], paragraph 15 & paragraph 19)
 

clear()XXDestroys all elements in the container. Invalidates all references, pointers, and iterators referring to the elements of the container and may invalidate the past-the-end iterator. ([sequence.reqmts], Table 100)
std::vector
 
    





reserve()XX

After reserve(), capacity() is greater or equal to the argument of reserve if reallocation happens and is equal to the previous value of capacity() otherwise. Reallocation invalidates all the references, pointers, and iterators referring to the elements in the sequence. ([vector.capacity], paragraph 3 & paragraph 6)

 

insert(), emplace_back(), emplace(), push_back()XX

Causes reallocation if the new size is greater than the old capacity. If no reallocation happens, all the iterators and references before the insertion point remain valid. ([vector.modifiers], paragraph 1). All iterators and references after the insertion point are invalidated.

 


erase(), pop_back(), resize()XXInvalidates iterators and references at or after the point of the erase. ([vector.modifiers], paragraph 3)
 

clear()XXDestroys all elements in the container. Invalidates all references, pointers, and iterators referring to the elements of the container and may invalidate the past-the-end iterator. ([sequence.reqmts], Table 100)
std::set, std::multiset, std::map, std::multimap
      





erase(), clear()XXInvalidates only iterators and references to the erased elements. ([associative.reqmts], paragraph 9)

std::unordered_set, std::unordered_multiset, std::unordered_map, std::unordered_multimap

    





erase(), clear()XXInvalidates only iterators and references to the erased elements. ([unord.req], paragraph 14)
 

insert(), emplace()X
 

The insert and emplace members shall not affect the validity of iterators if (N+n) < z * B, where N is the number of elements in the container prior to the insert operation, n is the number of elements inserted, B is the container’s bucket count, and z is the container’s maximum load factor. ([unord.req], paragraph 15)

 


rehash(), reserve()X
 

Rehashing invalidates iterators, changes ordering between elements, and changes which buckets the elements appear in but does not invalidate pointers or references to elements. ([unord.req], paragraph 9)

std::valarrayresize()
 

XResizing invalidates all pointers and references to elements in the array. ([valarray.members], paragraph 12)

A std::basic_string object is also a container to which this rule applies. For more specific information pertaining to std::basic_string containers, see STR52-CPP. Use valid references, pointers, and iterators to reference elements of a basic_string.

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Using invalid references, pointers, or iterators to reference elements of a container results in undefined behavior.

Rule

Severity

Likelihood

Remediation Cost

Priority

Level

CTR51-CPP

High

Probable

High

P6

L2

Automated Detection

Tool

Version

Checker

Description

   

Astrée

Include Page
Astrée_V
Astrée_V

overflow_upon_dereference
CodeSonar
Include Page
CodeSonar_V
CodeSonar_V

ALLOC.UAF

Use After Free

Helix QAC

Include Page
Helix QAC_V
Helix QAC_V

DF4746, DF4747, DF4748, DF4749


Klocwork
Include Page
Klocwork_V
Klocwork_V

ITER.CONTAINER.MODIFIED


Parasoft C/C++test

Include Page
Parasoft_V
Parasoft_V

CERT_CPP-CTR51-a

Do not modify container while iterating over it
Polyspace Bug Finder

Include Page
Polyspace Bug Finder_V
Polyspace Bug Finder_V

CERT C++: CTR51-CPP

Checks for use of invalid iterator (rule partially covered).

PVS-Studio

Include Page
PVS-Studio_V
PVS-Studio_V

V783
 

Related Vulnerabilities

Search for vulnerabilities resulting from the violation of this rule on the CERT website.

Related Guidelines

Bibliography

[ISO/IEC 14882-2014]

Clause 23, "Containers Library"
Subclause 24.2.1, "In General" 

[Kalev 1999]ANSI/ISO C++ Professional Programmer's Handbook
[Meyers 2001]Item 43, "Prefer Algorithm Calls to Handwritten Loops"
[Sutter 2004]Item 84, "Prefer Algorithm Calls to Handwritten Loops"

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