# Manual browser: tanh(3)

TANH(3) | Library Functions Manual | TANH(3) |

# NAME

**tanh**,

**tanhf**— hyperbolic tangent function

# LIBRARY

Math Library (libm, -lm)# DESCRIPTION

The**tanh**() and

**tanhf**() functions compute the hyperbolic tangent of

*x*. For a discussion of error due to roundoff, see math(3).

# RETURN VALUES

Upon successful completion, these functions return the hyperbolic tangent value. The following may also occur:-
If
*x*is ± 0,*x*is returned. -
If
*x*is NaN, a NaN is returned. -
If
*x*is positive infinity, a value 1 is returned; if*x*is negative infinity, -1 is returned. -
If
*x*is subnormal, a range error can occur and*x*is returned.

# STANDARDS

The described functions conform to ISO/IEC 9899:1999 (“ISO C99”).September 18, 2011 | NetBSD 7.0 |