Compute an inverse hyperbolic tangent
#include <math.h> double atanh( double x ); float atanhf( float x ); long double atanhl( long double x );
These functions compute the inverse hyperbolic tangent of x.
To check for error situations, use feclearexcept() and fetestexcept(). For example:
The inverse hyperbolic tangent of x.
If x is: | These functions return: | Errors: |
---|---|---|
±0.0 | x | — |
±1.0 | Inf, with the same sign as x | FE_DIVBYZERO |
Finite and |x| > 1 | NaN | FE_INVALID |
±Inf | NaN | FE_INVALID |
NaN | NaN | — |
These functions raise FE_INEXACT if the FPU reports that the result can't be exactly represented as a floating-point number.
#include <stdio.h> #include <math.h> #include <fenv.h> #include <stdlib.h> int main( void ) { int except_flags; feclearexcept(FE_ALL_EXCEPT); printf( "%f\n", atanh( 0.5 ) ); except_flags = fetestexcept(FE_ALL_EXCEPT); if(except_flags) { /* An error occurred; handle it appropriately. */ } return EXIT_SUCCESS; }
produces the output:
0.549306
Safety: | |
---|---|
Cancellation point | No |
Interrupt handler | No |
Signal handler | No |
Thread | Yes |