COPYSIGN(3)		   Linux Programmers Manual		  COPYSIGN(3)



NAME
       copysign, copysignf, copysignl - copy sign of a number

SYNOPSIS
       #include 

       double copysign(double x, double y);
       float copysignf(float x, float y);
       long double copysignl(long double x, long double y);

       Link with -lm.

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       copysign(), copysignf(), copysignl(): _SVID_SOURCE || _BSD_SOURCE ||
       _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE; or cc -std=c99

DESCRIPTION
       The copysign() functions return a value whose  absolute	value  matches
       that of x, but whose sign bit matches that of y.  If x is a NaN, then a
       NaN with the sign bit of y is returned.

CONFORMING TO
       C99, 4.3BSD.  This function is defined in IEC  559  (and  the  appendix
       with recommended functions in IEEE 754/IEEE 854).

NOTES
       On architectures where the floating-point formats are not IEEE 754 com
       pliant, the copysign() functions may treat a negative zero as positive.

SEE ALSO
       signbit(3)

COLOPHON
       This  page  is  part of release 3.05 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.



GNU				  2007-07-26			   COPYSIGN(3)