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.

DESCRIPTION

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

NOTES

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

CONFORMING TO

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

SEE ALSO

signbit(3)