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RINT(3P)                   POSIX Programmer's Manual                  RINT(3P)
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.1-2008
       defers to the ISO C standard.
       These  functions shall return the integral value (represented as a dou-
       ble) nearest x in the direction of the current rounding mode. The  cur-
       rent rounding mode is implementation-defined.
       If  the  current  rounding  mode  rounds toward negative infinity, then
       rint() shall be equivalent to floor().  If the  current  rounding  mode
       rounds  toward  positive  infinity,  then rint() shall be equivalent to
       ceil().  If the current rounding mode rounds towards zero, then  rint()
       shall  be  equivalent  to trunc().  If the current rounding mode rounds
       towards nearest, then rint() differs from round() in that halfway cases
       are rounded to even rather than away from zero.
       These  functions differ from the nearbyint(), nearbyintf(), and nearby-
       intl() 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  over-
       flow.
RATIONALE
       None.
FUTURE DIRECTIONS
       None.
SEE ALSO
       abs(), ceil(), feclearexcept(), fetestexcept(), floor(), isnan(), near-
       byint()
       The Base Definitions volume of POSIX.1-2008, Section 4.19, Treatment of
       Error Conditions for Mathematical Functions, <math.h>
COPYRIGHT
       Portions  of  this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri-
       cal  and  Electronics  Engineers,  Inc  and  The  Open Group.  (This is
       POSIX.1-2008 with the 2013 Technical Corrigendum  1  applied.)  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.unix.org/online.html .
       Any typographical or formatting errors that appear  in  this  page  are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors,  see  https://www.ker-
       nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group                  2013                             RINT(3P)