проверить, не упорядочены ли аргументы (test if arguments are unordered)
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)
isunordered — test if arguments are unordered
Синопсис (Synopsis)
#include <math.h>
int isunordered(real-floating x, real-floating y);
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 isunordered() macro shall determine whether its arguments are
unordered.
Возвращаемое значение (Return value)
Upon successful completion, the isunordered() macro shall return
1 if its arguments are unordered, and 0 otherwise.
If x or y is NaN, 1 shall be returned.
Ошибки (Error)
No errors are defined.
The following sections are informative.
Примеры (Examples)
None.
Использование в приложениях (Application usage)
The relational and equality operators support the usual
mathematical relationships between numeric values. For any
ordered pair of numeric values, exactly one of the relationships
(less, greater, and equal) is true. Relational operators may
raise the invalid floating-point exception when argument values
are NaNs. For a NaN and a numeric value, or for two NaNs, just
the unordered relationship is true. This macro is a quiet (non-
floating-point exception raising) version of a relational
operator. It facilitates writing efficient code that accounts for
NaNs without suffering the invalid floating-point exception. In
the SYNOPSIS section, real-floating indicates that the argument
shall be an expression of real-floating type.
Обоснование (Rationale)
None.
Будущие направления (Future directions)
None.
Смотри также (See also)
isgreater(3p), isgreaterequal(3p), isless(3p), islessequal(3p),
islessgreater(3p)
The Base Definitions volume of POSIX.1‐2017, math.h(0p)
