функции остатка (remainder functions)
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)
remquo, remquof, remquol — remainder functions
Синопсис (Synopsis)
#include <math.h>
double remquo(double x, double y, int *quo);
float remquof(float x, float y, int *quo);
long double remquol(long double x, long double y, int *quo);
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 remquo(), remquof(), and remquol() functions shall compute
the same remainder as the remainder(), remainderf(), and
remainderl() functions, respectively. In the object pointed to by
quo, they store a value whose sign is the sign of x/y and whose
magnitude is congruent modulo 2n to the magnitude of the integral
quotient of x/y, where n is an implementation-defined integer
greater than or equal to 3. If y is zero, the value stored in the
object pointed to by quo is unspecified.
An application wishing to check for error situations should set
errno to zero and call feclearexcept(FE_ALL_EXCEPT) before
calling these functions. On return, if errno is non-zero or
fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW |
FE_UNDERFLOW) is non-zero, an error has occurred.
Возвращаемое значение (Return value)
These functions shall return x REM y.
On systems that do not support the IEC 60559 Floating-Point
option, if y is zero, it is implementation-defined whether a
domain error occurs or zero is returned.
If x or y is NaN, a NaN shall be returned.
If x is ±Inf or y is zero and the other argument is non-NaN, a
domain error shall occur, and a NaN shall be returned.
Ошибки (Error)
These functions shall fail if:
Domain Error
The x argument is ±Inf, or the y argument is ±0 and
the other argument is non-NaN.
If the integer expression (math_errhandling &
MATH_ERRNO) is non-zero, then errno shall be set to
[EDOM]. If the integer expression (math_errhandling
& MATH_ERREXCEPT) is non-zero, then the invalid
floating-point exception shall be raised.
These functions may fail if:
Domain Error
The y argument is zero.
If the integer expression (math_errhandling &
MATH_ERRNO) is non-zero, then errno shall be set to
[EDOM]. If the integer expression (math_errhandling
& MATH_ERREXCEPT) is non-zero, then the invalid
floating-point exception shall be raised.
The following sections are informative.
Примеры (Examples)
None.
Использование в приложениях (Application usage)
On error, the expressions (math_errhandling & MATH_ERRNO) and
(math_errhandling & MATH_ERREXCEPT) are independent of each
other, but at least one of them must be non-zero.
Обоснование (Rationale)
These functions are intended for implementing argument reductions
which can exploit a few low-order bits of the quotient. Note that
x may be so large in magnitude relative to y that an exact
representation of the quotient is not practical.
Будущие направления (Future directions)
None.
Смотри также (See also)
feclearexcept(3p), fetestexcept(3p), remainder(3p)
The Base Definitions volume of POSIX.1‐2017, Section 4.20,
Treatment of Error Conditions for Mathematical Functions,
math.h(0p)
