copysign(3) [netbsd man page]

COPYSIGN(3)						   BSD Library Functions Manual 					       COPYSIGN(3)

NAME

     copysign, copysignf, copysignl -- functions to manipulate signs

LIBRARY

     Math Library (libm, -lm)

SYNOPSIS

     #include <math.h>

     double
     copysign(double x, double y);

     float
     copysignf(float x, float y);

     long double
     copysignl(long double x, long double y);

DESCRIPTION

     The copysign(), copysignf(), and copysignl() functions return a value whose absolute value matches x, but whose sign bit is taken from y.

RETURN VALUES

     Upon successful completion, all three functions return a value with the magnitude of x and the sign of y.	If x is NaN , the functions return
     a NaN with the sign of y.

SEE ALSO

     math(3), signbit(3)

STANDARDS

     The described functions conform to ISO/IEC 9899:1999 (``ISO C99'').

CAVEATS

     Note that on implementations that represent a signed zero but do not treat negative zero consistently in arithmetic operations, these func-
     tions may regard the sign of zero as positive.

BSD
								  April 13, 2011							       BSD

COPYSIGN(3)						     Linux Programmer's Manual						       COPYSIGN(3)

NAME

       copysign, copysignf, copysignl - copy sign of a number

SYNOPSIS

       #include <math.h>

       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 || _POSIX_C_SOURCE >= 200112L;
	   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.

       For example, copysign(42.0, -1.0) and copysign(-42.0, -1.0) both return -42.0.

RETURN VALUE

       On success, these functions return a value whose magnitude is taken from x and whose sign is taken from y.

       If x is a NaN, a NaN with the sign bit of y is returned.

ERRORS

       No errors occur.

CONFORMING TO

       C99, POSIX.1-2001.  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 compliant, the copysign() functions may treat a negative zero as posi-
       tive.

SEE ALSO

       signbit(3)

COLOPHON

       This page is part of release 3.44 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
								    2012-03-25							       COPYSIGN(3)