ATANH(3POSIX)

💖 ATANH(3POSIX) — the POSIX Programmer's Manual, bestie edition 💖

okay so real talk first, bestie: this page lives in the POSIX Programmer's Manual. That means the Linux version of this interface might act differently (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. no cap. 🫶

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✨ PROLOG ✨

This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

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🌸 NAME 🌸

atanh, atanhf, atanhl — inverse hyperbolic tangent functions 💅

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🦋 SYNOPSIS 🦋

#include <math.h>

double atanh(double x);
float atanhf(float x);
long double atanhl(long double x);

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👑 DESCRIPTION 👑

The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional — like, not on purpose, periodt. This volume of POSIX.1‐2017 defers to the ISO C standard.

These functions shall compute the inverse hyperbolic tangent of their argument x. that's it, that's the job. 🎀

If your app wants to check for error situations, you gotta 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, an error has occurred. vibe check complete. ✨

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💜 RETURN VALUE 💜

Upon successful completion, these functions shall return the inverse hyperbolic tangent of their argument.

If x is ±1, a pole error shall occur, and atanh(), atanhf(), and atanhl() shall return the value of the macro HUGE_VAL, HUGE_VALF, and HUGE_VALL, respectively, with the same sign as the correct value of the function.

For finite |x|>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 ±0, x shall be returned.

If x is ±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.

If x is not returned, atanh(), atanhf(), and atanhl() shall return an implementation-defined value no greater in magnitude than DBL_MIN, FLT_MIN, and LDBL_MIN, respectively.

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💀 ERRORS 💀

These functions shall fail if:

Domain Error

The x argument is finite and not in the range [-1,1], or is ±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.

Pole Error

The x argument is ±1.

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 divide-by-zero floating-point exception shall be raised.

These functions may fail if:

Range Error

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.

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🍓 EXAMPLES 🍓

None.

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🧚 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. like they're not besties, they don't text each other, but one of them HAS to show up. 🙈

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🌈 RATIONALE 🌈

None.

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⭐ FUTURE DIRECTIONS ⭐

None.

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🔥 SEE ALSO 🔥

• feclearexcept()
• fetestexcept()
• tanh()

The Base Definitions volume of POSIX.1‐2017, Section 4.20, Treatment of Error Conditions for Mathematical Functions, <math.h>

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📜 COPYRIGHT 📜

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 .

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and that's the whole page, bestie!! 🎀✨ this one came to you from IEEE/The Open Group, dated 2017, and it's filed under ATANH(3POSIX). slay, go compute some inverse hyperbolic tangents responsibly, mwah 💅💖