функция остаточного значения точки (point remainder value function)
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)
fmod, fmodf, fmodl — floating-point remainder value function
Синопсис (Synopsis)
#include <math.h>
double fmod(double x, double y);
float fmodf(float x, float y);
long double fmodl(long double x, long double 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.
These functions shall return the floating-point remainder of the
division of x by y.
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 the value x-i*y, for some integer i
such that, if y is non-zero, the result has the same sign as x
and magnitude less than the magnitude of y.
If the correct value would cause underflow, and is not
representable, a range error may occur, and fmod(), modf(), and
fmodl() shall return 0.0, or (if the IEC 60559 Floating-Point
option is not supported) an implementation-defined value no
greater in magnitude than DBL_MIN, FLT_MIN, and LDBL_MIN,
respectively.
If x or y is NaN, a NaN shall be returned, and none of the
conditions below shall be considered.
If y is zero, a domain error shall occur, and a NaN shall be
returned.
If x is infinite, a domain error shall occur, and a NaN shall be
returned.
If x is ±0 and y is not zero, ±0 shall be returned.
If x is not infinite and y is ±Inf, x shall be returned.
If the correct value would cause underflow, and is representable,
a range error may occur and the correct value shall be returned.
Ошибки (Error)
These functions shall fail if:
Domain Error
The x argument is infinite or y 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.
These functions may fail if:
Range Error The result underflows.
If the integer expression (math_errhandling &
MATH_ERRNO) is non-zero, then errno shall be set to
[ERANGE]. If the integer expression
(math_errhandling & MATH_ERREXCEPT) is non-zero, then
the underflow 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)
None.
Будущие направления (Future directions)
None.
Смотри также (See also)
feclearexcept(3p), fetestexcept(3p), isnan(3p)
Section 4.20, Treatment of Error Conditions for Mathematical
Functions, math.h(0p)
