1FETESTEXCEPT(3P)           POSIX Programmer's Manual          FETESTEXCEPT(3P)
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PROLOG

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

12       fetestexcept — test floating-point exception flags
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SYNOPSIS

15       #include <fenv.h>
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17       int fetestexcept(int excepts);
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DESCRIPTION

20       The functionality described on this reference page is aligned with  the
21       ISO C  standard.  Any  conflict between the requirements described here
22       and the ISO C standard is unintentional. This  volume  of  POSIX.1‐2017
23       defers to the ISO C standard.
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25       The fetestexcept() function shall determine which of a specified subset
26       of the floating-point exception flags are currently  set.  The  excepts
27       argument specifies the floating-point status flags to be queried.
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RETURN VALUE

30       The  fetestexcept()  function  shall  return  the value of the bitwise-
31       inclusive OR of the floating-point exception  macros  corresponding  to
32       the currently set floating-point exceptions included in excepts.
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ERRORS

35       No errors are defined.
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37       The following sections are informative.
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EXAMPLES

40       The  following  example  calls  function f() if an invalid exception is
41       set, and then function g() if an overflow exception is set:
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44           #include <fenv.h>
45           /* ... */
46           {
47               #pragma STDC FENV_ACCESS ON
48               int set_excepts;
49               feclearexcept(FE_INVALID | FE_OVERFLOW);
50               // maybe raise exceptions
51               set_excepts = fetestexcept(FE_INVALID | FE_OVERFLOW);
52               if (set_excepts & FE_INVALID) f();
53               if (set_excepts & FE_OVERFLOW) g();
54               /* ... */
55           }
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APPLICATION USAGE

58       None.
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RATIONALE

61       None.
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FUTURE DIRECTIONS

64       None.
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SEE ALSO

67       feclearexcept(), fegetexceptflag(), feraiseexcept()
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69       The Base Definitions volume of POSIX.1‐2017, <fenv.h>
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72       Portions of this text are reprinted and reproduced in  electronic  form
73       from  IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
74       table Operating System Interface (POSIX), The Open Group Base  Specifi‐
75       cations  Issue  7, 2018 Edition, Copyright (C) 2018 by the Institute of
76       Electrical and Electronics Engineers, Inc and The Open Group.   In  the
77       event of any discrepancy between this version and the original IEEE and
78       The Open Group Standard, the original IEEE and The Open Group  Standard
79       is  the  referee document. The original Standard can be obtained online
80       at http://www.opengroup.org/unix/online.html .
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82       Any typographical or formatting errors that appear  in  this  page  are
83       most likely to have been introduced during the conversion of the source
84       files to man page format. To report such errors,  see  https://www.ker‐
85       nel.org/doc/man-pages/reporting_bugs.html .
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89IEEE/The Open Group                  2017                     FETESTEXCEPT(3P)
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