atanh(), atanhf() inverse hyperbolic tangent function	Function
	SYNOPSIS DESCRIPTION PARAMETERS RETURN VALUES CONFORMANCE MULTITHREAD SAFETY LEVEL PORTING ISSUES AVAILABILITY SEE ALSO

---

SYNOPSIS

#include <math.h>

double atanh(double x)

float atanhf(float x)

---

DESCRIPTION

The atanh() and atanhf() functions compute the inverse hyperbolic tangent of the real argument x.

---

PARAMETERS

x 

Is a value between -1.0 and 1.0, exclusive.

---

RETURN VALUES

The atanh() function returns the inverse hyperbolic tangent.

If x is greater than 1.0 or x is NaN, then:

• if in IEEE mode, a value of NaN is returned.

• if in POSIX mode, a value of NaN is returned.

• if in SVID or XOPEN mode, NaN is returned and matherr() is called.

If the absolute value of x is 1.0, a value of infinity is returned. If in POSIX mode, errno is set to EDOM.

If x is NaN, atanh() returns NaN.

---

CONFORMANCE

atanh(): UNIX 98

atanhf(): PTC MKS Toolkit UNIX APIs extension

---

MULTITHREAD SAFETY LEVEL

MT-Safe.

---

PORTING ISSUES

None.

---

AVAILABILITY

PTC MKS Toolkit for Professional Developers
PTC MKS Toolkit for Professional Developers 64-Bit Edition
PTC MKS Toolkit for Enterprise Developers
PTC MKS Toolkit for Enterprise Developers 64-Bit Edition

---

SEE ALSO

Functions:

acosh(), asinh(), exp(), math(), matherr()

---

PTC MKS Toolkit 10.4 Documentation Build 39.