1FLOOR(3)                   Linux Programmer's Manual                  FLOOR(3)
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NAME

6       floor,  floorf,  floorl - largest integral value not greater than argu‐
7       ment
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SYNOPSIS

10       #include <math.h>
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12       double floor(double x);
13       float floorf(float x);
14       long double floorl(long double x);
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16       Link with -lm.
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18   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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20       floorf(), floorl():
21           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
22               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
23               || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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DESCRIPTION

26       These functions return the largest integral value that is  not  greater
27       than x.
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29       For example, floor(0.5) is 0.0, and floor(-0.5) is -1.0.
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RETURN VALUE

32       These functions return the floor of x.
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34       If x is integral, +0, -0, NaN, or an infinity, x itself is returned.
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ERRORS

37       No  errors  occur.  POSIX.1-2001 documents a range error for overflows,
38       but see NOTES.
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ATTRIBUTES

41       For an  explanation  of  the  terms  used  in  this  section,  see  at‐
42       tributes(7).
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44       ┌────────────────────────────────────────────┬───────────────┬─────────┐
45       │Interface                                   │ Attribute     │ Value   │
46       ├────────────────────────────────────────────┼───────────────┼─────────┤
47       │floor(), floorf(), floorl()                 │ Thread safety │ MT-Safe │
48       └────────────────────────────────────────────┴───────────────┴─────────┘
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CONFORMING TO

51       C99, POSIX.1-2001, POSIX.1-2008.
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53       The variant returning double also conforms to SVr4, 4.3BSD, C89.
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NOTES

56       SUSv2 and POSIX.1-2001 contain text about overflow (which might set er‐
57       rno to ERANGE, or raise an FE_OVERFLOW exception).   In  practice,  the
58       result  cannot  overflow on any current machine, so this error-handling
59       stuff is just nonsense.  (More precisely, overflow can happen only when
60       the maximum value of the exponent is smaller than the number of mantis‐
61       sa bits.  For the IEEE-754 standard 32-bit  and  64-bit  floating-point
62       numbers  the maximum value of the exponent is 128 (respectively, 1024),
63       and the number of mantissa bits is 24 (respectively, 53).)
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SEE ALSO

66       ceil(3), lrint(3), nearbyint(3), rint(3), round(3), trunc(3)
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COLOPHON

69       This page is part of release 5.13 of the Linux  man-pages  project.   A
70       description  of  the project, information about reporting bugs, and the
71       latest    version    of    this    page,    can     be     found     at
72       https://www.kernel.org/doc/man-pages/.
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76                                  2021-03-22                          FLOOR(3)
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