copysign(3) - NetBSD Manual Pages

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COPYSIGN(3)             NetBSD 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.

NetBSD 6.0.4                    April 13, 2011                    NetBSD 6.0.4