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       nearbyint, nearbyintf, nearbyintl, rint, rintf, rintl - round to nearest integer


       #include <math.h>

       double nearbyint(double x);
       float nearbyintf(float x);
       long double nearbyintl(long double x);

       double rint(double x);
       float rintf(float x);
       long double rintl(long double x);

       Link with -lm.

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

       nearbyint(), nearbyintf(), nearbyintl():
           _POSIX_C_SOURCE >= 200112L || _ISOC99_SOURCE
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
               || _XOPEN_SOURCE >= 500
               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
       rintf(), rintl():
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE


       The  nearbyint(),  nearbyintf(),  and  nearbyintl()  functions  round their argument to an
       integer value  in  floating-point  format,  using  the  current  rounding  direction  (see
       fesetround(3))  and  without  raising  the  inexact  exception.  When the current rounding
       direction is to nearest, these functions round  halfway  cases  to  the  even  integer  in
       accordance with IEEE-754.

       The  rint(),  rintf(),  and  rintl()  functions  do  the  same, but will raise the inexact
       exception (FE_INEXACT, checkable via fetestexcept(3)) when the  result  differs  in  value
       from the argument.


       These functions return the rounded integer value.

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


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


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

       │InterfaceAttributeValue   │
       │nearbyint(), nearbyintf(), │ Thread safety │ MT-Safe │
       │nearbyintl(), rint(),      │               │         │
       │rintf(), rintl()           │               │         │


       C99, POSIX.1-2001, POSIX.1-2008.


       SUSv2  and  POSIX.1-2001  contain 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 maximum 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 number of mantissa bits  is  24
       (respectively, 53).)

       If you want to store the rounded value in an integer type, you probably want to use one of
       the functions described in lrint(3) instead.


       ceil(3), floor(3), lrint(3), round(3), trunc(3)


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       project,  information  about  reporting  bugs, and the latest version of this page, can be
       found at

                                            2017-09-15                                    RINT(3)