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 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()
       . If the current rounding mode rounds toward positive infinity, then rint() shall be equivalent to ceil()
       .

       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.

       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()  ,  nearbyint()  ,  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(P)