asinh(3) Library Functions Manual asinh(3)

# NAME¶

asinh, asinhf, asinhl - inverse hyperbolic sine function

# LIBRARY¶

Math library (libm, -lm)

# SYNOPSIS¶

`#include <math.h>`
```double asinh(double x);
float asinhf(float x);
long double asinhl(long double x);```

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

asinh():

```
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L

|| _XOPEN_SOURCE >= 500

|| /* Since glibc 2.19: */ _DEFAULT_SOURCE

|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE```

asinhf(), asinhl():

```
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L

|| /* Since glibc 2.19: */ _DEFAULT_SOURCE

|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE```

# DESCRIPTION¶

These functions calculate the inverse hyperbolic sine of x; that is the value whose hyperbolic sine is x.

# RETURN VALUE¶

On success, these functions return the inverse hyperbolic sine of x.

If x is a NaN, a NaN is returned.

If x is +0 (-0), +0 (-0) is returned.

If x is positive infinity (negative infinity), positive infinity (negative infinity) is returned.

No errors occur.

# ATTRIBUTES¶

For an explanation of the terms used in this section, see attributes(7).

 Interface Attribute Value asinh (), asinhf (), asinhl () Thread safety MT-Safe

# STANDARDS¶

C11, POSIX.1-2008.

# HISTORY¶

C99, POSIX.1-2001.

The variant returning double also conforms to SVr4, 4.3BSD.