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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
       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().
       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.
       If x is NaN, a NaN shall be returned.
       If x is +-0 or +-Inf, x shall be returned.
       If  the  correct  value would cause overflow, a range error shall occur
       and rint(), rintf(), and rintl() shall return the value  of  the  macro
       +-HUGE_VAL,  +-HUGE_VALF,  and  +-HUGE_VALL  (with the same sign as x),
       respectively.
ERRORS
       These functions shall fail if:
       Range Error
              The result would cause an overflow.
       If the integer expression (math_errhandling & MATH_ERRNO) is  non-zero,
       then  errno  shall  be  set  to  [ERANGE].  If  the  integer expression
       (math_errhandling & MATH_ERREXCEPT)  is  non-zero,  then  the  overflow
       floating-point exception shall be raised.

       The following sections are informative.
EXAMPLES
       None.
APPLICATION USAGE
       On   error,   the   expressions  (math_errhandling  &  MATH_ERRNO)  and
       (math_errhandling & MATH_ERREXCEPT) are independent of each other,  but
       at least one of them must be non-zero.
RATIONALE
       None.
FUTURE DIRECTIONS
       None.
SEE ALSO
       abs(), ceil(), feclearexcept(), fetestexcept(), floor(), isnan(), near-
       byint(), the Base Definitions volume of  IEEE Std 1003.1-2001,  Section
       4.18,   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, 2003 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
       Specifications  Issue  6,  Copyright  (C) 2001-2003 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open  Group.  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.opengroup.org/unix/online.html .

IEEE/The Open Group                  2003                             RINT(3P)