The functions in this section are related to the exponential functions; see Exponents and Logarithms.

— Function: double **sinh** (`double x`)

— Function: floatsinhf(float x)

— Function: long doublesinhl(long double x)

Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.

These functions return the hyperbolic sine of

x, defined mathematically as`(exp (`

x`) - exp (-`

x`)) / 2`

. They may signal overflow ifxis too large.

— Function: double **cosh** (`double x`)

— Function: floatcoshf(float x)

— Function: long doublecoshl(long double x)

Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.

These function return the hyperbolic cosine of

x, defined mathematically as`(exp (`

x`) + exp (-`

x`)) / 2`

. They may signal overflow ifxis too large.

— Function: double **tanh** (`double x`)

— Function: floattanhf(float x)

— Function: long doubletanhl(long double x)

Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.

These functions return the hyperbolic tangent of

x, defined mathematically as`sinh (`

x`) / cosh (`

x`)`

. They may signal overflow ifxis too large.

There are counterparts for the hyperbolic functions which take complex arguments.

— Function: complex double **csinh** (`complex double z`)

— Function: complex floatcsinhf(complex float z)

— Function: complex long doublecsinhl(complex long double z)

Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.

These functions return the complex hyperbolic sine of

z, defined mathematically as`(exp (`

z`) - exp (-`

z`)) / 2`

.

— Function: complex double **ccosh** (`complex double z`)

— Function: complex floatccoshf(complex float z)

— Function: complex long doubleccoshl(complex long double z)

Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.

These functions return the complex hyperbolic cosine of

z, defined mathematically as`(exp (`

z`) + exp (-`

z`)) / 2`

.

— Function: complex double **ctanh** (`complex double z`)

— Function: complex floatctanhf(complex float z)

— Function: complex long doublectanhl(complex long double z)

Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.

These functions return the complex hyperbolic tangent of

z, defined mathematically as`csinh (`

z`) / ccosh (`

z`)`

.

— Function: double **asinh** (`double x`)

— Function: floatasinhf(float x)

— Function: long doubleasinhl(long double x)

Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.

These functions return the inverse hyperbolic sine of

x—the value whose hyperbolic sine isx.

— Function: double **acosh** (`double x`)

— Function: floatacoshf(float x)

— Function: long doubleacoshl(long double x)

Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.

These functions return the inverse hyperbolic cosine of

x—the value whose hyperbolic cosine isx. Ifxis less than`1`

,`acosh`

signals a domain error.

— Function: double **atanh** (`double x`)

— Function: floatatanhf(float x)

— Function: long doubleatanhl(long double x)

Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.

These functions return the inverse hyperbolic tangent of

x—the value whose hyperbolic tangent isx. If the absolute value ofxis greater than`1`

,`atanh`

signals a domain error; if it is equal to 1,`atanh`

returns infinity.

— Function: complex double **casinh** (`complex double z`)

— Function: complex floatcasinhf(complex float z)

— Function: complex long doublecasinhl(complex long double z)

Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.

These functions return the inverse complex hyperbolic sine of

z—the value whose complex hyperbolic sine isz.

— Function: complex double **cacosh** (`complex double z`)

— Function: complex floatcacoshf(complex float z)

— Function: complex long doublecacoshl(complex long double z)

Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.

These functions return the inverse complex hyperbolic cosine of

z—the value whose complex hyperbolic cosine isz. Unlike the real-valued functions, there are no restrictions on the value ofz.

— Function: complex double **catanh** (`complex double z`)

— Function: complex floatcatanhf(complex float z)

— Function: complex long doublecatanhl(complex long double z)

Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.

These functions return the inverse complex hyperbolic tangent of

z—the value whose complex hyperbolic tangent isz. Unlike the real-valued functions, there are no restrictions on the value ofz.