As i can see In D3DX first params is almost (if not always) an output value/parameter, the same thing it returns. Now it is removed and you just use returned value.
Although this confuses me too, shouldn't here be Vec3TransformNormal instead Vec3TransformCoord since we are talking about directions?
// "dx11" camTarget = XMVector3TransformCoord(DefaultForward, camRotationMatrix ); // "dx9" D3DXVec3TransformCoord(&camTarget, &DefaultForward, &camRotationMatrix); // although you could use return value if you need to fill some variable with same values as camTarget receives from this function otherVec3 = *D3DXVec3TransformCoord(&camTarget, &DefaultForward, &camRotationMatrix);
// "dx11" camRotationMatrix = XMMatrixRotationRollPitchYaw(camPitch, camYaw, 0); // "dx9" D3DXMatrixRotationRollPitchYaw(&camRotationMatrix, camPitch, camYaw, 0);