int fun ( int para )
{
  int stat;

  if ( para >= 0 )
  {
    //...

    stat = 1;
  }
  else
  {
    //...

    stat = -1;
  }

  return ( stat );
}

int main ( void )
{
  int local = 0;
  int sign  = 0;

  //...

  sign = fun ( local );    //遵循1

  //...

  ( void ) fun ( local );  //遵循2

  //...

  return ( 0 );
}