Examples of errors detected by the V751 diagnostic

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

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);
}

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],
                     ....);
  ....
}

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;
}

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;
}

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.

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);
  }
}

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

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;
}