# rint

## PROLOG



           This manual page is part of the POSIX Programmer's Manual.  The
           Linux implementation of this interface may differ (consult the
           corresponding Linux manual page for details of Linux behavior), or
           the interface may not be implemented on Linux.
    


## NAME



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


## SYNOPSIS



           #include <math.h>
    
           double rint(double _x_);
           float rintf(float _x_);
           long double rintl(long double _x_);
    


## DESCRIPTION



           The functionality described on this reference page is aligned with
           the ISO C standard. Any conflict between the requirements
           described here and the ISO C standard is unintentional. This
           volume of POSIX.1‐2017 defers to the ISO C standard.
    
           These functions shall return the integral value (represented as a
           **double**) nearest _x_ in 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 to floor(3p).  If the current rounding
           mode rounds toward positive infinity, then _rint_() shall be
           equivalent to ceil(3p).  If the current rounding mode rounds
           towards zero, then _rint_() shall be equivalent to trunc(3p).  If
           the current rounding mode rounds towards nearest, then _rint_()
           differs from round(3p) in that halfway cases are rounded to even
           rather than away from zero.
    
           These functions differ from the _nearbyint_(), _nearbyintf_(), and
           _nearbyintl_() 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
           _errno_ to zero and call _feclearexcept_(FE_ALL_EXCEPT) before calling
           these functions. On return, if _errno_ is non-zero or
           _fetestexcept_(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW |
           FE_UNDERFLOW) is non-zero, an error has occurred.
    


## RETURN VALUE



           Upon successful completion, these functions shall return the
           integer (represented as a double precision number) nearest _x_ in
           the direction of the current rounding mode.  The result shall have
           the same sign as _x_.
    
           If _x_ is NaN, a NaN shall be returned.
    
           If _x_ is ±0 or ±Inf, _x_ shall be returned.
    


## ERRORS



           No errors are defined.
    
           _The following sections are informative._
    


## EXAMPLES



           None.
    


## APPLICATION USAGE



           The integral value returned by these functions need not be
           expressible as an **intmax_t**.  The return value should be tested
           before assigning it to an integer type to avoid the undefined
           results of an integer overflow.
    


## RATIONALE



           None.
    


## FUTURE DIRECTIONS



           None.
    


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