asinh, asinhf, asinhl - inverse hyperbolic sine functions
double asinh(double x);
float asinhf(float x);
long double asinhl(long double x);
[CX] 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. This volume of POSIX.1-2017 defers to the ISO C standard.
These functions shall compute the inverse hyperbolic sine of their argument x.
An application wishing to check for error situations should set errno to zero and call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if errno is non-zero or fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error has occurred.
Upon successful completion, these functions shall return the inverse hyperbolic sine of their argument.
[MX] If x is NaN, a NaN shall be returned.
If x is ±0, or ±Inf, x shall be returned.
If x is subnormal, a range error may occur
[MXX] and x should be returned.
[MX] If x is not returned, asinh(), asinhf(), and asinhl() shall return an implementation-defined value no greater in magnitude than DBL_MIN, FLT_MIN, and LDBL_MIN, respectively.
These functions may fail if:
- Range Error
- [MX] 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.
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.
feclearexcept, fetestexcept, sinh
XBD Treatment of Error Conditions for Mathematical Functions, <math.h>
First released in Issue 4, Version 2.
Moved from X/OPEN UNIX extension to BASE.
The asinh() function is no longer marked as an extension.
The asinhf() and asinhl() functions are added for alignment with the ISO/IEC 9899:1999 standard.
The DESCRIPTION, RETURN VALUE, ERRORS, and APPLICATION USAGE sections are revised to align with the ISO/IEC 9899:1999 standard.
IEC 60559:1989 standard floating-point extensions over the ISO/IEC 9899:1999 standard are marked.
POSIX.1-2008, Technical Corrigendum 1, XSH/TC1-2008/0036  is applied.
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