xref: /freebsd/lib/msun/man/ieee_test.3 (revision 3642298923e528d795e3a30ec165d2b469e28b40)
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32.\"     from: @(#)ieee.3	6.4 (Berkeley) 5/6/91
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35.Dd March 10, 1994
36.Dt IEEE_TEST 3
37.Os
38.Sh NAME
39.Nm logb ,
40.Nm logbf ,
41.Nm scalb ,
42.Nm scalbf ,
43.Nm significand ,
44.Nm significandf
45.Nd IEEE test functions
46.Sh LIBRARY
47.Lb libm
48.Sh SYNOPSIS
49.In math.h
50.Ft double
51.Fn logb "double x"
52.Ft float
53.Fn logbf "float x"
54.Ft double
55.Fn scalb "double x" "double n"
56.Ft float
57.Fn scalbf "float x" "float n"
58.Ft double
59.Fn significand "double x"
60.Ft float
61.Fn significandf "float x"
62.Sh DESCRIPTION
63These functions allow users to test conformance to
64.St -ieee754 .
65Their use is not otherwise recommended.
66.Pp
67.Fn logb x
68and
69.Fn logbf x
70return
71.Fa x Ns 's exponent
72.Fa n ,
73a signed integer converted to double\-precision floating\-point.
74.Fn logb \*(Pm\*(If
75= +\*(If;
76.Fn logb 0
77= -\*(If with a division by zero exception.
78.Pp
79.Fn scalb x n
80and
81.Fn scalbf x n
82return
83.Fa x Ns \(**(2** Ns Fa n )
84computed by exponent manipulation.
85If
86.Fa n
87is not an integer, \*(Pm\*(If, or an \*(Na, the result is unspecified.
88.Pp
89.Fn significand x
90and
91.Fn significandf x
92return
93.Fa sig ,
94where
95.Fa x
96:=
97.Fa sig No \(** 2** Ns Fa n
98with 1 \(<=
99.Fa sig
100< 2.
101.Fn significand x
102and
103.Fn significandf x
104are not defined when
105.Fa x
106is 0, \*(Pm\*(If, or \*(Na.
107.Sh SEE ALSO
108.Xr ieee 3 ,
109.Xr math 3
110.Sh STANDARDS
111.St -ieee754
112