xref: /freebsd/lib/msun/man/cimag.3 (revision a0409676120c1e558d0ade943019934e0f15118d)
1.\" Copyright (c) 2004 Stefan Farfeleder
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25.\" $FreeBSD$
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27.Dd August 7, 2008
28.Dt CIMAG 3
29.Os
30.Sh NAME
31.Nm cimag , cimagf , cimagl ,
32.Nm conj , conjf , conjl ,
33.Nm cproj , cprojf , cprojl ,
34.Nm creal , crealf , creall
35.Nd "functions to manipulate complex numbers"
36.Sh LIBRARY
37.Lb libm
38.Sh SYNOPSIS
39.In complex.h
40.Ft double
41.Fn cimag "double complex z"
42.Ft float
43.Fn cimagf "float complex z"
44.Ft "long double"
45.Fn cimagl "long double complex z"
46.Ft "double complex"
47.Fn conj "double complex z"
48.Ft "float complex"
49.Fn conjf "float complex z"
50.Ft "long double complex"
51.Fn conjl "long double complex z"
52.Ft "double complex"
53.Fn cproj "double complex z"
54.Ft "float complex"
55.Fn cprojf "float complex z"
56.Ft "long double complex"
57.Fn cprojl "long double complex z"
58.Ft double
59.Fn creal "double complex z"
60.Ft float
61.Fn crealf "float complex z"
62.Ft "long double"
63.Fn creall "long double complex z"
64.Sh DESCRIPTION
65Let
66.Sm off
67.Fa a + b * Em i
68.Sm on
69denote the complex number
70.Fa z .
71.Pp
72The
73.Fn creal
74functions return the real part
75.Fa a ,
76and the
77.Fn cimag
78functions return the imaginary part
79.Fa b .
80.Pp
81The
82.Fn conj
83functions return the complex conjugate
84.Sm off
85.Fa a - b * Em i .
86.Sm on
87.Pp
88The
89.Fn cproj
90functions return the projection onto the Riemann sphere.
91If
92.Fa z
93contains an infinite component, then the result is
94.Fa \*(If \*(Pm 0 Ns * Ns Em i ,
95where the (zero) imaginary part of the result has the same sign as
96.Fa b .
97Otherwise, the result is
98.Fa z .
99.Pp
100These functions do not signal any floating point exceptions.
101.Sh STANDARDS
102The
103.Fn cimag ,
104.Fn conj ,
105.Fn cproj ,
106and
107.Fn creal
108functions conform to
109.St -isoC-99 .
110.Sh HISTORY
111The
112.Fn cimag ,
113.Fn conj
114and
115.Fn creal
116functions first appeared in
117.Fx 5.3 .
118The
119.Fn cproj
120functions appeared in
121.Fx 8.0 .
122