FETESTEXCEPT(3)            POSIX Programmer's Manual           FETESTEXCEPT(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
       fetestexcept -- test floating-point exception flags

SSYYNNOOPPSSIISS
       #include <fenv.h>

       int fetestexcept(int _e_x_c_e_p_t_s);

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_t_e_s_t_e_x_c_e_p_t() function shall determine which of a specified subset
       of the floating-point exception flags are currently set. The _e_x_c_e_p_t_s
       argument specifies the floating-point status flags to be queried.

RREETTUURRNN VVAALLUUEE
       The _f_e_t_e_s_t_e_x_c_e_p_t() function shall return the value of the bitwise-
       inclusive OR of the floating-point exception macros corresponding to
       the currently set floating-point exceptions included in _e_x_c_e_p_t_s.

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 calls function _f() if an invalid exception is
       set, and then function _g() if an overflow exception is set:


           #include <fenv.h>
           /* ... */
           {
               #pragma STDC FENV_ACCESS ON
               int set_excepts;
               feclearexcept(FE_INVALID | FE_OVERFLOW);
               // maybe raise exceptions
               set_excepts = fetestexcept(FE_INVALID | FE_OVERFLOW);
               if (set_excepts & FE_INVALID) f();
               if (set_excepts & FE_OVERFLOW) g();
               /* ... */
           }

AAPPPPLLIICCAATTIIOONN UUSSAAGGEE
       None.

RRAATTIIOONNAALLEE
       None.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       _f_e_c_l_e_a_r_e_x_c_e_p_t(), _f_e_g_e_t_e_x_c_e_p_t_f_l_a_g(), _f_e_r_a_i_s_e_e_x_c_e_p_t()

       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                      FETESTEXCEPT(3)
