копировать знак числа (copy sign of a number)
Имя (Name)
copysign, copysignf, copysignl - copy sign of a number
Синопсис (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.
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
copysign(), copysignf(), copysignl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
Описание (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.
Возвращаемое значение (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.
Ошибки (Error)
No errors occur.
Атрибуты (Attributes)
For an explanation of the terms used in this section, see
attributes(7).
┌──────────────────────────────────────┬───────────────┬─────────┐
│Interface │ Attribute │ Value │
├──────────────────────────────────────┼───────────────┼─────────┤
│copysign(), copysignf(), copysignl() │ Thread safety │ MT-Safe │
└──────────────────────────────────────┴───────────────┴─────────┘
Стандарты (Conforming to)
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).
Примечание (Note)
On architectures where the floating-point formats are not IEEE
754 compliant, these functions may treat a negative zero as
positive.
Смотри также (See also)
signbit(3)
