1ASIN(3P)                   POSIX Programmer's Manual                  ASIN(3P)
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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.
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11

NAME

13       asin, asinf, asinl — arc sine function
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SYNOPSIS

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

23       The functionality described on this reference page is aligned with  the
24       ISO C  standard.  Any  conflict between the requirements described here
25       and the ISO C standard is unintentional. This  volume  of  POSIX.1‐2008
26       defers to the ISO C standard.
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28       These  functions  shall  compute the principal value of the arc sine of
29       their argument x.  The value of x should be in the range [−1,1].
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31       An application wishing to check for error situations should  set  errno
32       to  zero  and  call  feclearexcept(FE_ALL_EXCEPT)  before calling these
33       functions. On return, if errno is non-zero or fetestexcept(FE_INVALID |
34       FE_DIVBYZERO  |  FE_OVERFLOW  | FE_UNDERFLOW) is non-zero, an error has
35       occurred.
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RETURN VALUE

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

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

84       None.
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APPLICATION USAGE

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

92       None.
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FUTURE DIRECTIONS

95       None.
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SEE ALSO

98       feclearexcept(), fetestexcept(), isnan(), sin()
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100       The Base Definitions volume of POSIX.1‐2008, Section 4.19, Treatment of
101       Error Conditions for Mathematical Functions, <math.h>
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104       Portions  of  this text are reprinted and reproduced in electronic form
105       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
106       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
107       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
108       cal  and  Electronics  Engineers,  Inc  and  The  Open Group.  (This is
109       POSIX.1-2008 with the 2013 Technical Corrigendum  1  applied.)  In  the
110       event of any discrepancy between this version and the original IEEE and
111       The Open Group Standard, the original IEEE and The Open Group  Standard
112       is  the  referee document. The original Standard can be obtained online
113       at http://www.unix.org/online.html .
114
115       Any typographical or formatting errors that appear  in  this  page  are
116       most likely to have been introduced during the conversion of the source
117       files to man page format. To report such errors,  see  https://www.ker
118       nel.org/doc/man-pages/reporting_bugs.html .
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122IEEE/The Open Group                  2013                             ASIN(3P)
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