|TANH(3P)||POSIX Programmer's Manual||TANH(3P)|
double tanh(double x); float tanhf(float x); long double tanhl(long double x);
These functions shall compute the hyperbolic tangent 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.
If x is NaN, a NaN shall be returned.
If x is ±0, x shall be returned.
If x is ±Inf, ±1 shall be returned.
If x is subnormal, a range error may occur
and x should be returned.
If x is not returned, tanh(), tanhf(), and tanhl() shall return an implementation-defined value no greater in magnitude than DBL_MIN, FLT_MIN, and LDBL_MIN, respectively.
- Range Error
- 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.
The following sections are informative.
The Base Definitions volume of POSIX.1‐2017, Section 4.20, Treatment of Error Conditions for Mathematical Functions, <math.h>
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|2017||IEEE/The Open Group|