1FPCLASSIFY(3P)             POSIX Programmer's Manual            FPCLASSIFY(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       fpclassify — classify real floating type
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SYNOPSIS

15       #include <math.h>
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17       int fpclassify(real-floating x);
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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  fpclassify() macro shall classify its argument value as NaN, infi‐
26       nite, normal, subnormal, zero, or into  another  implementation-defined
27       category.   First,  an  argument represented in a format wider than its
28       semantic type is converted to its semantic type. Then classification is
29       based on the type of the argument.
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RETURN VALUE

32       The fpclassify() macro shall return the value of the number classifica‐
33       tion macro appropriate to the value of its argument.
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ERRORS

36       No errors are defined.
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38       The following sections are informative.
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EXAMPLES

41       None.
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APPLICATION USAGE

44       None.
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RATIONALE

47       None.
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FUTURE DIRECTIONS

50       None.
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SEE ALSO

53       isfinite(), isinf(), isnan(), isnormal(), signbit()
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55       The Base Definitions volume of POSIX.1‐2017, <math.h>
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58       Portions of this text are reprinted and reproduced in  electronic  form
59       from  IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
60       table Operating System Interface (POSIX), The Open Group Base  Specifi‐
61       cations  Issue  7, 2018 Edition, Copyright (C) 2018 by the Institute of
62       Electrical and Electronics Engineers, Inc and The Open Group.   In  the
63       event of any discrepancy between this version and the original IEEE and
64       The Open Group Standard, the original IEEE and The Open Group  Standard
65       is  the  referee document. The original Standard can be obtained online
66       at http://www.opengroup.org/unix/online.html .
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68       Any typographical or formatting errors that appear  in  this  page  are
69       most likely to have been introduced during the conversion of the source
70       files to man page format. To report such errors,  see  https://www.ker‐
71       nel.org/doc/man-pages/reporting_bugs.html .
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75IEEE/The Open Group                  2017                       FPCLASSIFY(3P)
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