1ASIN(3P)                   POSIX Programmer's Manual                  ASIN(3P)
2
3
4

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.
10

NAME

12       asin, asinf, asinl — arc sine function
13

SYNOPSIS

15       #include <math.h>
16
17       double asin(double x);
18       float asinf(float x);
19       long double asinl(long double x);
20

DESCRIPTION

22       The functionality described on this reference page is aligned with  the
23       ISO C  standard.  Any  conflict between the requirements described here
24       and the ISO C standard is unintentional. This  volume  of  POSIX.1‐2017
25       defers to the ISO C standard.
26
27       These  functions  shall  compute the principal value of the arc sine of
28       their argument x.  The value of x should be in the range [-1,1].
29
30       An application wishing to check for error situations should  set  errno
31       to  zero  and  call  feclearexcept(FE_ALL_EXCEPT)  before calling these
32       functions. On return, if errno is non-zero or fetestexcept(FE_INVALID |
33       FE_DIVBYZERO  |  FE_OVERFLOW  | FE_UNDERFLOW) is non-zero, an error has
34       occurred.
35

RETURN VALUE

37       Upon successful completion, these functions shall return the  arc  sine
38       of x, in the range [-π/2,π/2] radians.
39
40       For  finite  values  of x not in the range [-1,1], a domain error shall
41       occur, and either a NaN (if supported),  or  an  implementation-defined
42       value shall be returned.
43
44       If x is NaN, a NaN shall be returned.
45
46       If x is ±0, x shall be returned.
47
48       If x is ±Inf, a domain error shall occur, and a NaN shall be returned.
49
50       If x is subnormal, a range error may occur
51       and x should be returned.
52
53       If  x  is  not  returned,  asin(), asinf(), and asinl() shall return an
54       implementation-defined value no  greater  in  magnitude  than  DBL_MIN,
55       FLT_MIN, and LDBL_MIN, respectively.
56

ERRORS

58       These functions shall fail if:
59
60       Domain Error
61                   The x argument is finite and is not in the range [-1,1], or
62                   is ±Inf.
63
64                   If the integer expression (math_errhandling  &  MATH_ERRNO)
65                   is  non-zero,  then  errno  shall be set to [EDOM].  If the
66                   integer expression (math_errhandling &  MATH_ERREXCEPT)  is
67                   non-zero,  then  the invalid floating-point exception shall
68                   be raised.
69
70       These functions may fail if:
71
72       Range Error The value of x is subnormal.
73
74                   If the integer expression (math_errhandling  &  MATH_ERRNO)
75                   is  non-zero,  then errno shall be set to [ERANGE].  If the
76                   integer expression (math_errhandling &  MATH_ERREXCEPT)  is
77                   non-zero, then the underflow floating-point exception shall
78                   be raised.
79
80       The following sections are informative.
81

EXAMPLES

83       None.
84

APPLICATION USAGE

86       On  error,  the  expressions  (math_errhandling   &   MATH_ERRNO)   and
87       (math_errhandling  & MATH_ERREXCEPT) are independent of each other, but
88       at least one of them must be non-zero.
89

RATIONALE

91       None.
92

FUTURE DIRECTIONS

94       None.
95

SEE ALSO

97       feclearexcept(), fetestexcept(), isnan(), sin()
98
99       The Base Definitions volume of POSIX.1‐2017, Section 4.20, Treatment of
100       Error Conditions for Mathematical Functions, <math.h>
101
103       Portions  of  this text are reprinted and reproduced in electronic form
104       from IEEE Std 1003.1-2017, Standard for Information Technology --  Por‐
105       table  Operating System Interface (POSIX), The Open Group Base Specifi‐
106       cations Issue 7, 2018 Edition, Copyright (C) 2018 by the  Institute  of
107       Electrical  and  Electronics Engineers, Inc and The Open Group.  In the
108       event of any discrepancy between this version and the original IEEE and
109       The  Open Group Standard, the original IEEE and The Open Group Standard
110       is the referee document. The original Standard can be  obtained  online
111       at http://www.opengroup.org/unix/online.html .
112
113       Any  typographical  or  formatting  errors that appear in this page are
114       most likely to have been introduced during the conversion of the source
115       files  to  man page format. To report such errors, see https://www.ker
116       nel.org/doc/man-pages/reporting_bugs.html .
117
118
119
120IEEE/The Open Group                  2017                             ASIN(3P)
Impressum