[section:sign_functions Sign Manipulation Functions]

[h4 Synopsis]

``
#include <boost/math/special_functions/sign.hpp>
``

   namespace boost{ namespace math{
   
   template<class T> 
   int signbit(T x);
   
   template <class T>
   inline int sign (const T& z);

   template <class T>
   inline T copysign (const T& x, const T& y);
   
   }} // namespaces

[h4 Description]

   template<class T> 
   int signbit(T x);

Returns a non-zero value if the sign bit is set in variable /x/, otherwise `0`.
   
   template <class T>
   inline int sign (const T& z);
   
Returns `1` if `x > 0`, `-1` if `x < 0`, and `0` if x is zero.

   template <class T>
   inline T copysign (const T& x, const T& y);

Sets the sign of /x/ to be the same as the sign of /y/.

[endsect][/section:sign_functions Sign Manipulation Functions]
[/ 
  Copyright 2006 John Maddock and Paul A. Bristow.
  Distributed under the Boost Software License, Version 1.0.
  (See accompanying file LICENSE_1_0.txt or copy at
  http://www.boost.org/LICENSE_1_0.txt).
]