тестовый знак (test sign)
Пролог (Prolog)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
Имя (Name)
signbit — test sign
Синопсис (Synopsis)
#include <math.h>
int signbit(real-floating x);
Описание (Description)
The functionality described on this reference page is aligned
with the ISO C standard. Any conflict between the requirements
described here and the ISO C standard is unintentional. This
volume of POSIX.1‐2017 defers to the ISO C standard.
The signbit() macro shall determine whether the sign of its
argument value is negative. NaNs, zeros, and infinities have a
sign bit.
Возвращаемое значение (Return value)
The signbit() macro shall return a non-zero value if and only if
the sign of its argument value is negative.
Ошибки (Error)
No errors are defined.
The following sections are informative.
Примеры (Examples)
None.
Использование в приложениях (Application usage)
None.
Обоснование (Rationale)
None.
Будущие направления (Future directions)
None.
Смотри также (See also)
fpclassify(3p), isfinite(3p), isinf(3p), isnan(3p), isnormal(3p)
The Base Definitions volume of POSIX.1‐2017, math.h(0p)
