ROUND(3)                   POSIX Programmer's Manual                  ROUND(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
       round, roundf, roundl -- round to the nearest integer value in a
       floating-point format

SSYYNNOOPPSSIISS
       #include <math.h>

       double round(double _x);
       float roundf(float _x);
       long double roundl(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.1-2008
       defers to the ISO C standard.

       These functions shall round their argument to the nearest integer value
       in floating-point format, rounding halfway cases away from zero,
       regardless of the current rounding direction.

RREETTUURRNN VVAALLUUEE
       Upon successful completion, these functions shall return the rounded
       integer value.  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.

       These functions may raise the inexact floating-point exception if the
       result differs in value from the argument.

RRAATTIIOONNAALLEE
       None.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       _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()

       The Base Definitions volume of POSIX.1-2008, _S_e_c_t_i_o_n _4_._1_9, _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, 2013 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, Copyright (C) 2013 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open Group.  (This is
       POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/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                  2013                             ROUND(3)
