NAME
copysign, copysignf, copysignl - copy sign of a number
LIBRARY
Math library (libm, -lm)
SYNOPSIS
#include <math.h>double copysign(double \nx\n, double \ny\n);\n
\nfloat copysignf(float \nx\n, float \ny\n);\n
\nlong double copysignl(long double \nx\n, long double \ny\n);copysign(), copysignf(), copysignl():
\n
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
\n
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
\n
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCEDESCRIPTION
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 |
VERSIONS
On architectures where the floating-point formats are not IEEE 754 compliant, these functions may treat a negative zero as positive.
STANDARDS
C11, POSIX.1-2008.
This function is defined in IEC 559 (and the appendix with recommended functions in IEEE 754/IEEE 854).
HISTORY
C99, POSIX.1-2001, 4.3BSD.
SEE ALSO
signbit(3)