| COPYSIGN(3) | Linux Programmer's Manual | COPYSIGN(3) |
copysign, copysignf, copysignl - copy sign of a number
#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.
copysign(), copysignf(), copysignl():
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 returned.
No errors occur.
For an explanation of the terms used in this section, see attributes(7).
| Interface | Attribute | Value |
| copysign (), copysignf (), copysignl () | Thread safety | MT-Safe |
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 5.10 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/.
| 2017-09-15 | GNU |