1ISLESS(3P)                 POSIX Programmer's Manual                ISLESS(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       isless - test if x is less than y
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SYNOPSIS

15       #include <math.h>
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17       int isless(real-floating x, real-floating y);
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DESCRIPTION

21       The isless() macro shall determine whether its first argument  is  less
22       than  its second argument. The value of isless( x, y) shall be equal to
23       (x) < (y); however, unlike (x) < (y), isless( x, y) shall not raise the
24       invalid floating-point exception when x and y are unordered.
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RETURN VALUE

27       Upon  successful  completion, the isless() macro shall return the value
28       of (x) < (y).
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30       If x or y is NaN, 0 shall be returned.
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ERRORS

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

38       None.
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APPLICATION USAGE

41       The relational and equality operators support  the  usual  mathematical
42       relationships  between  numeric values. For any ordered pair of numeric
43       values, exactly one of the relationships (less, greater, and equal)  is
44       true.  Relational operators may raise the invalid floating-point excep‐
45       tion when argument values are NaNs. For a NaN and a numeric  value,  or
46       for  two NaNs, just the unordered relationship is true. This macro is a
47       quiet (non-floating-point exception raising) version  of  a  relational
48       operator.  It facilitates writing efficient code that accounts for NaNs
49       without suffering the invalid floating-point exception. In the SYNOPSIS
50       section,  real-floating indicates that the argument shall be an expres‐
51       sion of real-floating type.
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RATIONALE

54       None.
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FUTURE DIRECTIONS

57       None.
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SEE ALSO

60       isgreater(),    isgreaterequal(),    islessequal(),    islessgreater(),
61       isunordered(),  the  Base  Definitions  volume of IEEE Std 1003.1-2001,
62       <math.h>
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65       Portions of this text are reprinted and reproduced in  electronic  form
66       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
67       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
68       Specifications  Issue  6,  Copyright  (C) 2001-2003 by the Institute of
69       Electrical and Electronics Engineers, Inc and The Open  Group.  In  the
70       event of any discrepancy between this version and the original IEEE and
71       The Open Group Standard, the original IEEE and The Open Group  Standard
72       is  the  referee document. The original Standard can be obtained online
73       at http://www.opengroup.org/unix/online.html .
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77IEEE/The Open Group                  2003                           ISLESS(3P)
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