math_aux.h

stl的源码

#ifndef __MATH_AUX_H
#define __MATH_AUX_H

#include <limits>

#undef __STD
#if !defined (STLPORT) || defined (_STLP_USE_NAMESPACES)
#  define __STD std::
#else
#  define __STD
#endif

/*
 * This function is not only used to compare floating point values with a tolerance,
 * it also leads to ambiguity problems if the called functions do not have the
 * right prototype.
 */
template <class _Tp>
bool are_equals(_Tp val, _Tp ref) {
  if (val < ref) {
    return (ref - val) <= __STD numeric_limits<_Tp>::epsilon();
  }
  else {
    return (val - ref) <= __STD numeric_limits<_Tp>::epsilon();
  }
}

#undef __STD

#endif // __MATH_AUX_H