roundl

       #include <math.h>

       double round(double x);
       float roundf(float x);
       long double roundl(long double x);

       Link with -lm.

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       round(), roundf(), roundl():
           _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
           _POSIX_C_SOURCE >= 200112L;
           or cc -std=c99

DESCRIPTION
       These functions round x to the nearest integer, but round halfway cases
       away  from  zero  (regardless  of  the  current rounding direction, see
       fenv(3)), instead of to the nearest even integer like rint(3).

       For example, round(0.5) is 1.0, and round(-0.5) is -1.0.

RETURN VALUE
       These functions return the rounded integer value.

       If x is integral, +0, -0, NaN,  or infinite, x itself is returned.

ERRORS
       No errors occur.  POSIX.1-2001 documents a range error  for  overflows,
       but see NOTES.

VERSIONS
       These functions first appeared in glibc in version 2.1.

ATTRIBUTES
       For   an   explanation   of   the  terms  used  in  this  section,  see
       attributes(7).

       +----------------------------+---------------+---------+
       |Interface                   | Attribute     | Value   |
       +----------------------------+---------------+---------+
       |round(), roundf(), roundl() | Thread safety | MT-Safe |
       +----------------------------+---------------+---------+
CONFORMING TO
       C99, POSIX.1-2001, POSIX.1-2008.

NOTES
       POSIX.1-2001 contains text about overflow (which  might  set  errno  to
       ERANGE,  or  raise  an FE_OVERFLOW exception).  In practice, the result
       cannot overflow on any current machine, so this error-handling stuff is
       just nonsense.  (More precisely, overflow can happen only when the max-
       imum value of the exponent is smaller than the number of mantissa bits.
       For  the IEEE-754 standard 32-bit and 64-bit floating-point numbers the
       maximum value of the exponent is 128 (respectively, 1024), and the num-
       http://www.kernel.org/doc/man-pages/.

                                  2015-04-19                          ROUND(3)
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