osx man page for round

ROUND(3)						   BSD Library Functions Manual 						  ROUND(3)

NAME
     round, lround, llround -- round to integral value, regardless of rounding direction

SYNOPSIS
     #include <math.h>

     double
     round(double x);

     long double
     roundl(long double x);

     float
     roundf(float x);

     long int
     lround(double x);

     long int
     lroundl(long double x);

     long int
     lroundf(float x);

     long long int
     llround(double x);

     long long int
     llroundl(long double x);

     long long int
     llroundf(float x);

DESCRIPTION
     The round() functions return the integral value nearest to x rounding half-way cases away from zero, regardless of the current rounding
     direction.

     The lround() and llround() functions return the integral value nearest to x (rounding half-way cases away from zero, regardless of the cur-
     rent rounding direction) in the return formats specified.	If the rounded value is outside the range of the return type, the numeric result
     is unspecified and the "invalid" floating-point exception is raised. A range error may occur if the magnitude of x is too large.

SPECIAL VALUES
     round(+-0) returns +-0.

     round(+-infinity) returns +-infinity.

     The round() functions may, but are not required to, raise the "inexact" floating-point exception for non-integer numeric arguments.

     The lround() and llround() functions need not raise the "inexact" floating-point exception for non-integer arguments that round to within the
     range of the return type.

NOTE
     The roundtol() function is deprecated.  Please use the C99 function lround() instead.

VECTOR OPERATIONS
     If you need to apply the round() function to SIMD vectors or arrays, using the following functions provided by the Accelerate.framework may
     give significantly better performance:

     #include <Accelerate/Accelerate.h>

     vFloat vnintf(vFloat x);
     void vvnintf(float *y, const float *x, const int *n);
     void vvnint(double *y, const double *x, const int *n);

SEE ALSO
     ceil(3), floor(3), trunc(3), math(3)

STANDARDS
     The round() , lround() , and llround() functions conform to ISO/IEC 9899:2011.

BSD
								   July 02, 2008							       BSD