Our website uses cookies to enhance your browsing experience.
Accept
to the top
close form

Fill out the form in 2 simple steps below:

Your contact information:

Step 1
Congratulations! This is your promo code!

Desired license type:

Step 2
Team license
Enterprise license
** By clicking this button you agree to our Privacy Policy statement
close form
Request our prices
New License
License Renewal
--Select currency--
USD
EUR
* By clicking this button you agree to our Privacy Policy statement

close form
Free PVS‑Studio license for Microsoft MVP specialists
* By clicking this button you agree to our Privacy Policy statement

close form
To get the licence for your open-source project, please fill out this form
* By clicking this button you agree to our Privacy Policy statement

close form
I am interested to try it on the platforms:
* By clicking this button you agree to our Privacy Policy statement

close form
check circle
Message submitted.

Your message has been sent. We will email you at


If you do not see the email in your inbox, please check if it is filtered to one of the following folders:

  • Promotion
  • Updates
  • Spam

Webinar: C++ semantics - 06.11

>
>
>
Examples of errors detected by the V654…

Examples of errors detected by the V654 diagnostic

V654. Condition of a loop is always true/false.


Apache HTTP Server

V654 The condition 'retry < 2' of loop is always true. mod_proxy_wstunnel mod_proxy_wstunnel.c 436


static int proxy_wstunnel_handler(....)
{
  int retry;
  ....
  retry = 0;
  while (retry < 2) {
    char *locurl = url;
    ....
    // Variable 'retry' is not used
    ....
  }
  ....
}

WebRTC

V654 The condition 'loopCnt < 5' of loop is always true. cpr_win_socket.c 746


#define TCP_PORT_RETRY_CNT  5

cpr_socket_t
cprSecSocConnect (char *host,
                  int     port,
                  int     ipMode,
                  boolean mode,
                  uint32_t tos,
                  uint16_t *localPort)
{
  ....
  uint16_t loopCnt  = 0;
  ....
  while (loopCnt < TCP_PORT_RETRY_CNT) {
    ....
    .... // loopCnt not changed
    ....
  }
  ....
}

Oracle VM Virtual Box

V654 The condition of loop is always true. suphardenedverifyprocess-win.cpp 1732


DECLHIDDEN(int) supHardNtLdrCacheOpen(const char *pszName, ....)
{
  ....
  uint32_t i = 0;
  while (i < RT_ELEMENTS(g_apszSupNtVpAllowedDlls))
    if (!strcmp(pszName, g_apszSupNtVpAllowedDlls[i]))
      break;
  ....
}

What is dangerous about this loop is that the counter value doesn't change, so if the very first array item doesn't coincide with 'pszName', we'll get an infinite loop.


K Desktop Environment

V654 The condition 'state != 1' of loop is always true. passwd.cpp 255


int PasswdProcess::ConversePasswd(....)
{
  ....
  state = 0;
  while (state != 1)
  {
    line = readLine();
    if (line.isNull())
    {
      // No more input... OK
      return 0;
    }
    if (isPrompt(line, "password"))
    {
      // Uh oh, another prompt. Not good!
      kill(m_Pid, SIGKILL);
      waitForChild();
      return PasswordNotGood;
    }
    m_Error += line + '\n'; // Collect error message
  }
  ....
}

Miranda NG

V654 The condition '5' of loop is always true. Xfire main.cpp 1110


extern "C" __declspec(dllexport) int  Load(void)
{
  ....
  for (i = MAX_PATH; 5; i--){
  ....
}

Similar errors can be found in some other places:

  • V654 The condition '5' of loop is always true. Xfire variables.cpp 194

Linux Kernel

V654 The condition 'i < 10' of loop is always true. qla3xxx.c 149


static int ql_wait_for_drvr_lock(struct ql3_adapter *qdev)
{
  int i = 0;

  while (i < 10) {
    if (i)
      ssleep(1);

    if (ql_sem_lock(qdev,
        QL_DRVR_SEM_MASK,
        (QL_RESOURCE_BITS_BASE_CODE | (qdev->mac_index)
         * 2) << 1)) {
      netdev_printk(KERN_DEBUG, qdev->ndev,
              "driver lock acquired\n");
      return 1;
    }
  }

  netdev_err(qdev->ndev,
             "Timed out waiting for driver lock...\n");
  return 0;
}

Unreal Engine 4

V654 The condition '!bFoundName' of loop is always true. edgraphutilities.cpp 244


void FEdGraphUtilities::RenameGraphCloseToName(....)
{
  bool bFoundName = false;

  FString NewName = BaseName;

  int32 NameIndex = StartIndex;
  while (!bFoundName)
  {
    if (Graph->Rename(*NewName, Graph->GetOuter(), REN_Test))
    {
      UBlueprint* BP = FBlueprintEditorUtils....;
      Graph->Rename(*NewName, Graph->GetOuter(), ....);
      return;
    }

    NewName = FString::Printf(TEXT("%s_%d"),*BaseName,NameIndex);
    ++NameIndex;
  }
}

EFL Core Libraries

V654 The condition of loop is always false. evas_font_query.c 376


EAPI void
evas_common_font_query_size(....)
{
  ....
  size_t cluster = 0;
  size_t cur_cluster = 0;
  ....
  do
  {
    cur_cluster = cluster + 1;

    glyph--;
    if (cur_w > ret_w)
    {
      ret_w = cur_w;
    }
  }
  while ((glyph > first_glyph) && (cur_cluster == cluster));
  ....
}

Ardour

V654 The condition 'tries < 8' of loop is always true. session_transport.cc 68


void
Session::add_post_transport_work (PostTransportWork ptw)
{
  PostTransportWork oldval;
  PostTransportWork newval;
  int tries = 0;

  while (tries < 8) {
    oldval = (PostTransportWork) g_atomic_int_get (....);
    newval = PostTransportWork (oldval | ptw);
    if (g_atomic_int_compare_and_exchange (....)) {
      /* success */
      return;
    }
  }

  error << "Could not set post transport work! ...." << endmsg;
}

RT-Thread

V654 CWE-834 The condition 'i <= 255' of loop is always true. drv_ft5x06.c 160


static int ft5x06_dump(void)
{
  uint8_t i;
  uint8_t reg_value;

  DEBUG_PRINTF("[FTS] Touch Chip\r\n");

  for (i = 0; i <= 255; i++)
  {
    _ft5x06_read(i, ®_value, 1);

    if (i % 8 == 7)
      DEBUG_PRINTF("0x%02X = 0x%02X\r\n", i, reg_value);
    else
      DEBUG_PRINTF("0x%02X = 0x%02X ", i, reg_value);
  }
  DEBUG_PRINTF("\n");

  return 0;
}

Android

V654 CWE-834 The condition 'gate_id <= 0xFF' of loop is always true. nfa_hci_utils.cc 248


#define NFA_HCI_LAST_PROP_GATE 0xFF

tNFA_HCI_DYN_GATE* nfa_hciu_alloc_gate(uint8_t gate_id,
                                       tNFA_HANDLE app_handle) {
  ....
  for (gate_id = NFA_HCI_FIRST_HOST_SPECIFIC_GENERIC_GATE;
       gate_id <= NFA_HCI_LAST_PROP_GATE; gate_id++) {
    if (gate_id == NFA_HCI_CONNECTIVITY_GATE) gate_id++;
    if (nfa_hciu_find_gate_by_gid(gate_id) == NULL) break;
  }

  if (gate_id > NFA_HCI_LAST_PROP_GATE) {
    LOG(ERROR) << StringPrintf(
        "nfa_hci_alloc_gate - no free Gate ID: %u  "
        "App Handle: 0x%04x", gate_id, app_handle);
    return (NULL);
  }
  ....
}

Android

V654 CWE-834 The condition '++ retries' of loop is always true. SimpleDecodingSource.cpp 226


status_t SimpleDecodingSource::doRead(....) {
  ....
  for (int retries = 0; ++retries; ) {
  ....
}

Stellarium

V654 The condition 'start_of_directory == - 1' of loop is always true. qzip.cpp 617


void QZipReaderPrivate::scanFiles()
{
  ....
  // find EndOfDirectory header
  int i = 0;
  int start_of_directory = -1;
  EndOfDirectory eod;
  while (start_of_directory == -1) {
    const int pos = device->size()
      - int(sizeof(EndOfDirectory)) - i;
    if (pos < 0 || i > 65535) {
      qWarning() << "QZip: EndOfDirectory not found";
      return;
    }

    device->seek(pos);
    device->read((char *)&eod, sizeof(EndOfDirectory));
    if (readUInt(eod.signature) == 0x06054b50)
      break;
    ++i;
  }
  ....
}

Haiku Operation System

V654 The condition 'specificSequence != sequence' of loop is always false. pthread_key.cpp 55


static void*
get_key_value(pthread_thread* thread, uint32 key, int32 sequence)
{
  pthread_key_data& keyData = thread->specific[key];
  int32 specificSequence;
  void* value;

  do {
    specificSequence = keyData.sequence;
    if (specificSequence != sequence)
      return NULL;

    value = keyData.value;
  } while (specificSequence != sequence);

  keyData.value = NULL;

  return value;
}

Doom 1

V654 [CWE-834] The condition 'player->pendingweapon == wp_nochange' of loop is always false. p_pspr.c 232


boolean P_CheckAmmo (player_t* player)
{
  ....
  do {
    if (....)
    {
      player->pendingweapon = wp_plasma;
    }
    else .... if (....)
    {
      player->pendingweapon = wp_bfg;
    }
    else
    {
      player->pendingweapon = wp_fist;
    }
  } while (player->pendingweapon == wp_nochange);
  ....
}

Newton Game Dynamics

V654 The condition 'i < count' of loop is always false. MultiBodyCar.cpp 942


void MultibodyBodyCar(DemoEntityManager* const scene)
{
  ....
  int count = 10;
  count = 0;
  for (int i = 0; i < count; i++)
  {
    for (int j = 0; j < count; j++)
    {
      dMatrix offset(location);
      offset.m_posit += dVector (j * 5.0f + 4.0f, 0.0f, i * 5.0f, 0.0f);
      //manager->CreateSportCar(offset, viperModel.GetData());
      manager->CreateOffRoadCar(offset, monsterTruck.GetData());
    }
  }
  ....
}

Free Heroes of Might and Magic II

V654 The condition 'i < originalPalette.size()' of loop is always false. battle_interface.cpp 3689


void Battle::Interface::RedrawActionBloodLustSpell( Unit & target )
{
  std::vector<std::vector<uint8_t> > originalPalette;
  if ( target.Modes( SP_STONE ) )
  {
    originalPalette.push_back( PAL::GetPalette( PAL::GRAY ) );
  }
  else if ( target.Modes( CAP_MIRRORIMAGE ) )
  {
    originalPalette.push_back( PAL::GetPalette( PAL::MIRROR_IMAGE ) );
  }
  if ( !originalPalette.empty() )
  {
    for ( size_t i = 1; i < originalPalette.size(); ++i )
    {
      originalPalette[0] = PAL::CombinePalettes( originalPalette[0],
                                                 originalPalette[i] );
    }
    fheroes2::ApplyPalette( unitSprite, originalPalette[0] );
  }
  ....
}

Snort

V654 The condition '!done' of loop is always true. log.c 207


void PrintNetData(....)
{
  int done;           /* flag */
  ....

  /* initialization */
  done = 0;
  ....

  /* loop thru the whole buffer */
  while(!done)
    {
      ....
    }
  ....
}

TheXTech

V654 The condition 'chunk_size > 0' of loop is always true. thextech image_size.cpp 211


static bool tryJPEG(SDL_RWops* file, uint32_t *w, uint32_t *h)
{
  ....
  size_t chunk_size = 0;
  ....
  do
  {
    SDL_memset(raw, 0, JPEG_BUFFER_SIZE);
    pos = SDL_RWtell(file);
    chunk_size = SDL_RWread(file, raw, 1, JPEG_BUFFER_SIZE);
    if(chunk_size == 0)
      break;

    head = findJpegHead(raw, JPEG_BUFFER_SIZE);
    if(head)
    {
      if(head + 20 >= raw + JPEG_BUFFER_SIZE)
      {
        SDL_RWseek(file, -20, RW_SEEK_CUR);
        continue; /* re-scan this place */
      }

      if(SDL_memcmp(head, "\xFF\xE1", 2) == 0) /* EXIF, skip it!*/
      {
        const Sint64 curPos = pos + (head - raw);
        Sint64 toSkip = BE16(head, 2); //-V629
        SDL_RWseek(file, curPos + toSkip + 2, RW_SEEK_SET);
        continue;
      }

      *h = BE16(head, 5);
      *w = BE16(head, 7);
      return true;
    }
  } while(chunk_size > 0);               // <=

  return false;
}

FlipperZero

V654 [CWE-834] The condition '!done' of loop is always true. ibutton-cli.cpp 253


void onewire_cli_search(Cli* cli) {
  ....
  bool done = false;
  ....
  while(!done) {
    if(onewire.search(address, true) != 1) {
      printf("Search finished\r\n");
      onewire.reset_search();
      done = true;
      return;
    } else {
      printf("Found: ");
      for(uint8_t i = 0; i < 8; i++) {
        printf("%02X", address[i]);
      }
    printf("\r\n");
    }
    delay(100);
  }
  ....
}

Captain Blood

V654 [CWE-834] The condition 'n >= 0' of loop is always true. resourceselect.cpp 42


typedef unsigned int dword;

TResourceSelectorWindow::TResourceSelectorWindow ()
{
  string PakPath;
  // ....
  miss->EditorGetPackPath(PakPath);
  //....
  for (dword n = PakPath.Size()-1; n >= 0; n--)
  {
    if (PakPath[n] == '\\')
    {
      PakPath.Delete(0, n+1);
      break;
    }
  }

  // ....
}