table of contents
copysign(3) | Library Functions Manual | copysign(3) |
NAME¶
copysign, copysignf, copysignl - copy sign of a number
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);
copysign(), copysignf(), copysignl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
DESCRIPTION¶
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.
RETURN VALUE¶
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.
ERRORS¶
No errors occur.
ATTRIBUTES¶
For an explanation of the terms used in this section, see attributes(7).
Interface | Attribute | Value |
copysign (), copysignf (), copysignl () | Thread safety | MT-Safe |
STANDARDS¶
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).
NOTES¶
On architectures where the floating-point formats are not IEEE 754 compliant, these functions may treat a negative zero as positive.
SEE ALSO¶
2023-02-05 | Linux man-pages 6.03 |