NAME

rint() − round-to-nearest function

SYNOPSIS

#include <math.h>

double rint(double x);

DESCRIPTION

rint() returns the integer (represented as a double precision number) nearest x in the direction of the current rounding mode. 

In the default rounding mode (round to nearest), rint(x) is the integer nearest x with the additional stipulation that if | rint(x) −x|=1/2, then rint(x) is even. 

If the current rounding mode rounds toward negative infinity, rint() is identical to floor().  If the current rounding mode rounds toward positive infinity, rint() is identical to ceil(). 

Another way to obtain an integer near x is to declare (in C):

double x;  int k;  k = x;

The HP C compiler rounds x toward 0 to get the integer k.  Note that if x is larger than k can accommodate, the value of k and the presence or absence of an integer overflow are hard to predict. 

To use this function, link in the math library by specifying −lm on the compiler or linker command line. 

RETURN VALUE

If x is ±INFINITY, the rint() function returns ±INFINITY respectively. 

If x is NaN, the rint() function returns NaN. 

ERRORS

No errors are defined. 

SEE ALSO

floor(3M), ceil(3M), fmod(3M), fabs(3M), fpgetround(3M), isinf(3M), isnan(3M). 

STANDARDS CONFORMANCE

rint(): XPG4.2

Hewlett-Packard Company  —  HP-UX Release 10.20:  July 1996