FEGETROUND(3)              POSIX Programmer's Manual             FEGETROUND(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
       fegetround, fesetround -- get and set current rounding direction

SSYYNNOOPPSSIISS
       #include <fenv.h>

       int fegetround(void);
       int fesetround(int _r_o_u_n_d);

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.

       The _f_e_g_e_t_r_o_u_n_d() function shall get the current rounding direction.

       The _f_e_s_e_t_r_o_u_n_d() function shall establish the rounding direction
       represented by its argument _r_o_u_n_d.  If the argument is not equal to the
       value of a rounding direction macro, the rounding direction is not
       changed.

RREETTUURRNN VVAALLUUEE
       The _f_e_g_e_t_r_o_u_n_d() function shall return the value of the rounding
       direction macro representing the current rounding direction or a
       negative value if there is no such rounding direction macro or the
       current rounding direction is not determinable.

       The _f_e_s_e_t_r_o_u_n_d() function shall return a zero value if and only if the
       requested rounding direction was established.

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
       The following example saves, sets, and restores the rounding direction,
       reporting an error and aborting if setting the rounding direction
       fails:


           #include <fenv.h>
           #include <assert.h>
           void f(int round_dir)
           {
               #pragma STDC FENV_ACCESS ON
               int save_round;
               int setround_ok;
               save_round = fegetround();
               setround_ok = fesetround(round_dir);
               assert(setround_ok == 0);
               /* ... */
               fesetround(save_round);
               /* ... */
           }

AAPPPPLLIICCAATTIIOONN UUSSAAGGEE
       None.

RRAATTIIOONNAALLEE
       None.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       The Base Definitions volume of POSIX.1-2017, <<ffeennvv..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                        FEGETROUND(3)
