ASIN(3P)

πŸ“¦ version 2017a, in alpine 3.22, alpine 3.23, alpine 3.24, arch rolling, nixpkgs unstable, opensuse-leap 16.0

πŸ¦‹ ASIN(3P) β€” bestie we're doing TRIG today πŸ’…

okay so real quick, the manual name is ASIN(3P) and yes it lives in the POSIX Programmer's Manual, we love her πŸ’–

✨ PROLOG ✨

So like, this page is part of the POSIX Programmer's Manual. That's the important context, bestie. The Linux implementation of this interface may differ (so like, go check the corresponding Linux manual page for the deets on Linux behavior), or honestly the interface might not even be implemented on Linux at all. πŸ™ˆ

πŸ‘‘ NAME πŸ‘‘

asin, asinf, asinl β€” arc sine function 🌈

🌸 SYNOPSIS 🌸

#include <math.h>

double asin(double x);
float asinf(float x);
long double asinl(long double x);

three of them!! one for each flavor of float, she's inclusive πŸ’œ

πŸ’« DESCRIPTION πŸ’«

The functionality described on this reference page is aligned with the ISO C standard. And like, any conflict between what's described here and the ISO C standard? Totally unintentional, no drama intended. This volume of POSIX.1‐2017 defers to the ISO C standard, periodt.

These functions shall compute the principal value of the arc sine of their argument x. And the value of x should be in the range [-1,1] β€” like stay in your lane bestie πŸŽ€

An application wishing to check for error situations should set errno to zero and call feclearexcept(FE_ALL_EXCEPT) before calling these functions. Then on return, if errno is non-zero, OR if fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero β€” an error has occurred. that's the vibe check right there πŸ”₯

⭐ RETURN VALUE ⭐

Upon successful completion, these functions shall return the arc sine of x, in the range [-Ο€/2,Ο€/2] radians. cute.

  • For finite values of x not in the range [-1,1], a domain error shall occur, and either a NaN (if supported), or an implementation-defined value shall be returned. 😭
  • If x is NaN, a NaN shall be returned.
  • If x is Β±0, x shall be returned.
  • If x is Β±Inf, a domain error shall occur, and a NaN shall be returned.
  • If x is subnormal, a range error may occur and x should be returned.

And if x is not returned, then asin(), asinf(), and asinl() shall return an implementation-defined value no greater in magnitude than DBL_MIN, FLT_MIN, and LDBL_MIN, respectively. slay, noted 🫢

πŸ’€ ERRORS πŸ’€

These functions shall fail if:

  • Domain Error β€” The x argument is finite and is not in the range [-1,1], or is Β±Inf.
    • If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall be set to [EDOM].
    • If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the invalid floating-point exception shall be raised.

These functions may fail if:

  • Range Error β€” The value of x is subnormal.
    • If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall be set to [ERANGE].
    • If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the underflow floating-point exception shall be raised.
The following sections are informative. (so like, casual reading, no rules here πŸ’…)

πŸŽ€ EXAMPLES πŸŽ€

None.

literally none. not me expecting examples and getting nothing πŸ˜­πŸ’€

🧚 APPLICATION USAGE 🧚

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

πŸ’œ RATIONALE πŸ’œ

None.

🌈 FUTURE DIRECTIONS 🌈

None.

(iconic of them honestly, nothing on the horizon)

πŸ”₯ SEE ALSO πŸ”₯

  • feclearexcept()
  • fetestexcept()
  • isnan()
  • sin()

The Base Definitions volume of POSIX.1‐2017:

  • Section 4.20, Treatment of Error Conditions for Mathematical Functions
  • <math.h>

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group.

In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .

okay that's the whole page bestie, mwah πŸ’‹ β€” this was brought to you by IEEE/The Open Group, dated 2017, and the page you just read is ASIN(3P). go forth and compute your arc sines responsibly, queen πŸ‘‘βœ¨

πŸ“¦ where this page comes from