RINT(3)                    POSIX Programmer's Manual                   RINT(3)



PPRROOLLOOGG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

NNAAMMEE
       rint, rintf, rintl -- round-to-nearest integral value

SSYYNNOOPPSSIISS
       #include <math.h>

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

DDEESSCCRRIIPPTTIIOONN
       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.1-2017
       defers to the ISO C standard.

       These functions shall return the integral value (represented as a
       ddoouubbllee) 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
       _r_i_n_t() shall be equivalent to _f_l_o_o_r().  If the current rounding mode
       rounds toward positive infinity, then _r_i_n_t() shall be equivalent to
       _c_e_i_l().  If the current rounding mode rounds towards zero, then _r_i_n_t()
       shall be equivalent to _t_r_u_n_c().  If the current rounding mode rounds
       towards nearest, then _r_i_n_t() differs from _r_o_u_n_d() in that halfway cases
       are rounded to even rather than away from zero.

       These functions differ from the _n_e_a_r_b_y_i_n_t(), _n_e_a_r_b_y_i_n_t_f(), and
       _n_e_a_r_b_y_i_n_t_l() 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 _e_r_r_n_o
       to zero and call _f_e_c_l_e_a_r_e_x_c_e_p_t(FE_ALL_EXCEPT) before calling these
       functions. On return, if _e_r_r_n_o is non-zero or _f_e_t_e_s_t_e_x_c_e_p_t(FE_INVALID |
       FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error has
       occurred.

RREETTUURRNN VVAALLUUEE
       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.

EERRRROORRSS
       No errors are defined.

       _T_h_e _f_o_l_l_o_w_i_n_g _s_e_c_t_i_o_n_s _a_r_e _i_n_f_o_r_m_a_t_i_v_e_.

EEXXAAMMPPLLEESS
       None.

AAPPPPLLIICCAATTIIOONN UUSSAAGGEE
       The integral value returned by these functions need not be expressible
       as an iinnttmmaaxx__tt.  The return value should be tested before assigning it
       to an integer type to avoid the undefined results of an integer
       overflow.

RRAATTIIOONNAALLEE
       None.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       _a_b_s(), _c_e_i_l(), _f_e_c_l_e_a_r_e_x_c_e_p_t(), _f_e_t_e_s_t_e_x_c_e_p_t(), _f_l_o_o_r(), _i_s_n_a_n(),
       _n_e_a_r_b_y_i_n_t()

       The Base Definitions volume of POSIX.1-2017, _S_e_c_t_i_o_n _4_._2_0, _T_r_e_a_t_m_e_n_t _o_f
       _E_r_r_o_r _C_o_n_d_i_t_i_o_n_s _f_o_r _M_a_t_h_e_m_a_t_i_c_a_l _F_u_n_c_t_i_o_n_s, <<mmaatthh..hh>>

CCOOPPYYRRIIGGHHTT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 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 .

       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.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017                              RINT(3)
