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.
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 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)
GNU 2002-08-10 COPYSIGN(3)