Originální popis anglicky:
nearbyint, nearbyintf, nearbyintl - floating-point rounding functions
Návod, kniha: POSIX Programmer's Manual
double nearbyint(double x);
float nearbyintf(float x);
long double nearbyintl(long double x);
These functions shall round their argument to an integer value in floating-point
format, using the current rounding direction and without raising the inexact
An application wishing to check for error situations should set errno
zero and call feclearexcept
(FE_ALL_EXCEPT) before calling these
functions. On return, if errno
is non-zero or
(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is
non-zero, an error has occurred.
Upon successful completion, these functions shall return the rounded integer
is NaN, a NaN shall be returned.
is ±0, ±0 shall be returned.
is ±Inf, x
shall be returned.
If the correct value would cause overflow, a range error shall occur and
(), and nearbyintl
() shall return
the value of the macro ±HUGE_VAL, ±HUGE_VALF, and
±HUGE_VALL (with the same sign as x
These functions shall fail if:
- Range Error
- The result would cause an overflow.
If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then
shall be set to [ERANGE]. If the integer expression
(math_errhandling & MATH_ERREXCEPT) is non-zero, then the overflow
floating-point exception shall be raised.
The following sections are informative.
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.
() , fetestexcept
() , the Base Definitions volume of
IEEE Std 1003.1-2001, Section 4.18, Treatment of Error
Conditions for Mathematical Functions, <math.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.opengroup.org/unix/online.html