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Annotation of 43BSDReno/lib/libm/common_source/floor.3, revision 1.1.1.1

1.1       root        1: .\" Copyright (c) 1985 Regents of the University of California.
                      2: .\" All rights reserved.  The Berkeley software License Agreement
                      3: .\" specifies the terms and conditions for redistribution.
                      4: .\"
                      5: .\"    @(#)floor.3     6.4 (Berkeley) 5/12/86
                      6: .\"
                      7: .TH FLOOR 3M  "May 12, 1986"
                      8: .UC 4
                      9: .SH NAME
                     10: fabs, floor, ceil, rint \- absolute value, floor, ceiling, and
                     11: round-to-nearest functions
                     12: .SH SYNOPSIS
                     13: .nf
                     14: .B #include <math.h>
                     15: .PP
                     16: .B double floor(x)
                     17: .B double x;
                     18: .PP
                     19: .B double ceil(x)
                     20: .B double x;
                     21: .PP
                     22: .B double fabs(x)
                     23: .B double x;
                     24: .PP
                     25: .B double rint(x)
                     26: .B double x;
                     27: .fi
                     28: .SH DESCRIPTION
                     29: Fabs returns the absolute value |\|x\||.
                     30: .PP
                     31: Floor returns the largest integer no greater than x.
                     32: .PP
                     33: Ceil returns the smallest integer no less than x.
                     34: .PP
                     35: Rint returns the integer (represented as a double precision number)
                     36: nearest x in the direction of the prevailing rounding mode.
                     37: .SH NOTES
                     38: On a VAX, rint(x) is equivalent to adding half to the magnitude
                     39: and then rounding towards zero.
                     40: .PP
                     41: In the default rounding mode, to nearest,
                     42: on a machine that conforms to IEEE 754,
                     43: rint(x) is the integer nearest x with the additional stipulation
                     44: that if |rint(x)\-x|=1/2 then rint(x) is even.
                     45: Other rounding modes can make rint act like floor, or like ceil,
                     46: or round towards zero.
                     47: .PP
                     48: Another way to obtain an integer near x is to declare (in C)
                     49: .RS
                     50: double x;\0\0\0\0 int k;\0\0\0\0k\0=\0x;
                     51: .RE
                     52: Most C compilers round x towards 0 to get the integer k, but
                     53: some do otherwise.
                     54: If in doubt, use floor, ceil, or rint first, whichever you intend.
                     55: Also note that, if x is larger than k can accommodate, the value of
                     56: k and the presence or absence of an integer overflow are hard to
                     57: predict.
                     58: .SH SEE ALSO
                     59: abs(3),
                     60: ieee(3M),
                     61: math(3M)

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