Examples of errors detected by the V783 diagnostic

V783. Possible dereference of invalid iterator 'X'.

OrcaSlicer

V783 Iterator 'it' is checked after it was used. Perhaps there is a mistake in program logic. Check lines: 3159, 3160. Selection.cpp 3160

void Selection::ensure_not_below_bed()
{
  // ....
  if (is_any_volume()) {
    for (unsigned int i : m_list) {
      GLVolume& volume = *(*m_volumes)[i];
      const std::pair<int, int> instance =
        std::make_pair(volume.object_idx(), volume.instance_idx());
      InstancesToZMap::const_iterator it = instances_max_z.find(instance);
      const double z_shift = SINKING_MIN_Z_THRESHOLD - it->second;    // <=
      if (it != instances_max_z.end() && z_shift > 0.0)               // <=
        volume.set_volume_offset(Z, volume.get_volume_offset(Z) + z_shift);
    }
  }
  // ....
}

Windows Terminal

V783 [CERT-CTR51-CPP] Dereferencing of the invalid iterator 'shades.end()' might take place. ColorHelper.cpp 194

winrt::Windows::UI::Color ColorHelper::GetAccentColor(
    const winrt::Windows::UI::Color& color
)
{
    ....
    auto shades = std::map<float, HSL>();
    ....

    // 3f is quite nice if the whole non-client area is painted
    constexpr auto readability = 1.75f;
    for (auto shade : shades)
    {
        if (shade.first >= readability)
        {
            return HslToRgb(shade.second);
        }
    }
    return HslToRgb(shades.end()->second);
}

qdEngine

V783 [CWE-119, CERT-CTR51-CPP] Dereferencing of the invalid iterator 'it1' might take place. qd_condition_group.cpp 58

bool qdConditionGroup::remove_condition(int condition_id)
{
  for(conditions_container_t::iterator it = conditions_.begin();
      it != conditions_.end();
      ++it)
  {
    if(*it > condition_id)
      (*it)--;
  }

  conditions_container_t::iterator it1 = std::find(conditions_.begin(),
                                                   conditions_.end(),
                                                   condition_id);
  if(it1 != conditions_.end())
    return false;

  conditions_.erase(it1);
  return true;
}

0 A.D.

V783 CWE-119 Dereferencing of the invalid iterator 'segments.end()' might take place. CCmpRallyPointRenderer.cpp 1290

void CCmpRallyPointRenderer::MergeVisibilitySegments(
  std::deque<SVisibilitySegment>& segments)
{
  ....
  segments.erase(segments.end());
  ....
}

Rosegarden

V783 Dereferencing of the invalid iterator 'beatTimeTs.end()' might take place. CreateTempoMapFromSegmentCommand.cpp 119

void
CreateTempoMapFromSegmentCommand::initialise(Segment *s)
{
 ....
 std::vector<timeT> beatTimeTs;
 ....
 for (int i = m_composition->...At(*beatTimeTs.begin() - 1) + 1;
          i <= m_composition->...At(*beatTimeTs.end() - 1); ++i){
 ....
}

Similar errors can be found in some other places:

• V783 Dereferencing of the invalid iterator 'm_segments.end()' might take place. StaffHeader.cpp 250

Rosegarden

V783 Dereferencing of the invalid iterator 'i' might take place. IconStackedWidget.cpp 126

void
IconStackedWidget::slotPageSelect()
{
  iconbuttons::iterator i = m_iconButtons.begin();
  int index = 0;
  while (((*i)->isChecked() == false) &&
         (i != m_iconButtons.end())) {
    ++i;
    index++;
  }
  m_pagePanel->setCurrentIndex(index);
}