copysign, copysignf, copysignl - copy sign of a number
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():
_POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
These 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.
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
For an explanation of the terms used in this section, see attributes(7).
C99, POSIX.1-2001, POSIX.1-2008. This function is defined in IEC 559 (and the
appendix with recommended functions in IEEE 754/IEEE 854).
On architectures where the floating-point formats are not IEEE 754 compliant,
these functions may treat a negative zero as positive.
This page is part of release 5.01 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the latest
version of this page, can be found at https://www.kernel.org/doc/man-pages/.
|copysign (), copysignf (), copysignl ()