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rint, rintf, rintl - round-to-nearest integral value

#include <math.h>

double rint(doublex);

float rintf(floatx);

long double rintl(long doublex);

These functions shall return the integral value (represented as a

double) nearestxin the direction of the current rounding mode. The current rounding mode is implementation-defined.If the current rounding mode rounds toward negative infinity, then

rint() shall be equivalent tofloor() . If the current rounding mode rounds toward positive infinity, thenrint() shall be equivalent toceil() .These functions differ from the

nearbyint(),nearbyintf(), andnearbyintl() functions only in that they may raise the inexact floating-point exception if the result differs in value from the argument.An application wishing to check for error situations should set

errnoto zero and callfeclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, iferrnois non-zero orfetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error has occurred.

Upon successful completion, these functions shall return the integer (represented as a double precision number) nearest

xin the direction of the current rounding mode.If

xis NaN, a NaN shall be returned.If

xis ±0 or ±Inf,xshall be returned.If the correct value would cause overflow, a range error shall occur and

rint(),rintf(), andrintl() shall return the value of the macro ±HUGE_VAL, ±HUGE_VALF, and ±HUGE_VALL (with the same sign asx), respectively.

These functions shall fail if:

If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then

Range Error The result would cause an overflow. errnoshall 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.

None.

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.

None.

None.

abs() ,ceil() ,feclearexcept() ,fetestexcept() ,floor() ,isnan() ,nearbyint() , 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 .

IEEE/The Open Group |
RINT (P) | 2003 |