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man pages section 3: Extended Library Functions, Volume 2

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Updated: Thursday, June 13, 2019
 
 

lrint(3M)

Name

lrint, lrintf, lrintl - round to nearest integer value using current rounding direction

Synopsis

c99 [ flag... ] file... –lm [ library... ]
#include <math.h>

long lrint(double x);
long lrintf(float x);
long lrintl(long double x);

Description

These functions round their argument to the nearest integer value, rounding according to the current rounding direction.

Return Values

Upon successful completion, these functions return the rounded integer value.

If x is NaN, a domain error occurs and an unspecified value is returned.

If x is +Inf, a domain error occurs and an unspecified value is returned.

If x is −Inf, a domain error occurs and an unspecified value is returned.

If the correct value is positive and too large to represent as a long, a domain error occurs and an unspecified value is returned.

If the correct value is negative and too large to represent as a long, a domain error occurs and an unspecified value is returned.

Errors

These functions will fail if:

Domain Error

The x argument is NaN or ±Inf, or the correct value is not representable as an integer.

If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the invalid floating-point exception is raised.

Usage

An application wanting to check for exceptions should call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an exception has been raised. An application should either examine the return value or check the floating point exception flags to detect exceptions.

Attributes

See attributes(7) for descriptions of the following attributes:

ATTRIBUTE TYPE
ATTRIBUTE VALUE
Interface Stability
Committed
Availability
system/library/math
MT-Level
MT-Safe
Standard

See Also

math.h(3HEAD), feclearexcept(3M), fetestexcept(3M), llrint(3M), attributes(7), standards(7)