Examples of errors detected by the V751 diagnostic

V751. Parameter is not used inside function's body.

Linux Kernel

V751 Parameter 'LCDheight' is not used inside function body. init.c 339

static
unsigned short
SiS_GetModeID(int VGAEngine, unsigned int VBFlags,
              int HDisplay, int VDisplay,
              int Depth, bool FSTN,
              int LCDwidth, int LCDheight)
{
  unsigned short ModeIndex = 0;

  switch(HDisplay)
  {
  case 320:
    if(VDisplay == 200) ModeIndex = ModeIndex_320x200[Depth];
    else if(VDisplay == 240) {
      if((VBFlags & CRT2_LCD) && (FSTN))
        ModeIndex = ModeIndex_320x240_FSTN[Depth];
      else
        ModeIndex = ModeIndex_320x240[Depth];
    }
    break;
  case 400:
    if((!(VBFlags & CRT1_LCDA)) ||
       ((LCDwidth >= 800) && (LCDwidth >= 600))) { // <=
      if(VDisplay == 300) ModeIndex = ModeIndex_400x300[Depth];
    }
    break;
  case 512:
    if((!(VBFlags & CRT1_LCDA)) ||
       ((LCDwidth >= 1024) && (LCDwidth >= 768))) { // <=
      if(VDisplay == 384) ModeIndex = ModeIndex_512x384[Depth];
    }
    break;
    ....
  }

  return ModeIndex;
}

Valgrind

V751 Parameter 'i2' is not used inside function body. host_tilegx_defs.c 1223

void genReload_TILEGX ( /*OUT*/ HInstr ** i1,
                        /*OUT*/ HInstr ** i2,
                        HReg rreg,
                        Int offsetB )
{
  TILEGXAMode *am;
  vassert(!hregIsVirtual(rreg));
  am = TILEGXAMode_IR(offsetB, TILEGXGuestStatePointer());

  switch (hregClass(rreg)) {
  case HRcInt64:
    *i1 = TILEGXInstr_Load(8, rreg, am);                 // <=
    break;
  case HRcInt32:
    *i1 = TILEGXInstr_Load(4, rreg, am);                 // <=
    break;
  default:
    ppHRegClass(hregClass(rreg));
    vpanic("genReload_TILEGX: unimplemented regclass");
    break;
  }
}

Similar errors can be found in some other places:

• V751 Parameter 'i2' is not used inside function body. host_mips_defs.c 2000

Steinberg SDKs

V751 Parameter 'column' is not used inside function body. pitchnamesdatabrowsersource.cpp 227

void PitchNamesDataBrowserSource::dbCellTextChanged(
  int32_t row, int32_t column, ....)
{
  if (pitchnames)
  {
    UString128 str (newText);
    if (str.getLength () == 0)
      pitchnames->removePitchName (0, (int16)row);
    else
      pitchnames->setPitchName (0, (int16)row, str);
  }
}

HarfBuzz

V751 Parameter 'right' is not used inside function body. hb-ot-kern-table.hh 115

inline int get_kerning (hb_codepoint_t left,
                        hb_codepoint_t right,
                        const char *end) const
{
  unsigned int l = (this+leftClassTable).get_class (left);
  unsigned int r = (this+leftClassTable).get_class (left);  // <=
  unsigned int offset = l * rowWidth + r * sizeof (FWORD);
  ....
}

Nice error due to Copy-Paste. One copied the line, but forgot to change the left with right twice.

System Shock

V751 Parameter 'Y' is not used inside function body. BTEST.C 67

fix Terrain( fix X, fix Y, int deriv ) {
  if( deriv == 0 )
    return fix_mul(...., (X - ....) );
  if( deriv == 1 )
    return fix_mul(...., (X - ....) );
  if( deriv == 2 ) return 0;
    return 0;
}

Godot Engine

V751 Parameter 'p_y' is not used inside function body. texture.cpp 1085

bool AtlasTexture::is_pixel_opaque(int p_x, int p_y) const {

  if (atlas.is_valid()) {
    return atlas->is_pixel_opaque(p_x + region.position.x + margin.position.x,
                                  p_x + region.position.y + margin.position.y);
  }

  return true;
}

Bullet Physics SDK

V751 Parameter 'halfExtentsZ' is not used inside function body. TinyRenderer.cpp 375

void TinyRenderObjectData::createCube(float halfExtentsX,
                                      float halfExtentsY,
                                      float halfExtentsZ,
                                      ....)
{
  ....
  m_model->addVertex(halfExtentsX * cube_vertices_textured[i * 9],
                     halfExtentsY * cube_vertices_textured[i * 9 + 1],
                     halfExtentsY * cube_vertices_textured[i * 9 + 2],
                     cube_vertices_textured[i * 9 + 4],
                     ....);
  ....
}

Overgrowth

V751 [CERT-MSC13-C] Parameter 'rayTo' is not used inside function body. btSoftBody.cpp 2148

btScalar btSoftBody::RayFromToCaster::rayFromToTriangle(
  const btVector3& rayFrom,
  const btVector3& rayTo,
  const btVector3& rayNormalizedDirection,
  const btVector3& a,
  const btVector3& b,
  const btVector3& c,
  btScalar maxt)
{
  static const btScalar ceps = -SIMD_EPSILON * 10;
  static const btScalar teps = SIMD_EPSILON * 10;

  const btVector3 n = btCross(b - a, c - a);
  const btScalar d = btDot(a, n);
  const btScalar den = btDot(rayNormalizedDirection, n);
  if (!btFuzzyZero(den))
  {
    const btScalar num = btDot(rayFrom, n) - d;
    const btScalar t = -num / den;
    if ((t > teps) && (t < maxt))
    {
      const btVector3 hit = rayFrom + rayNormalizedDirection * t;
      if ((btDot(n, btCross(a - hit, b - hit)) > ceps) &&
          (btDot(n, btCross(b - hit, c - hit)) > ceps) &&
          (btDot(n, btCross(c - hit, a - hit)) > ceps))
      {
        return (t);
      }
    }
  }
  return (-1);
}