atanh(3) Library Functions Manual atanh(3) atanh, atanhf, atanhl - (libm -lm) #include double atanh(double x); float atanhf(float x); long double atanhl(long double x); glibc ( feature_test_macros(7)): atanh(): _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 500 || /* glibc 2.19: */ _DEFAULT_SOURCE || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE atanhf(), atanhl(): _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE x x. x. x (NaN) NaN. x +0 (-0) +0 (-0). x +1 -1 HUGE_VAL HUGE_VALF HUGE_VALL . x 1 NaN. math_error(7) . : : x -1 +1 errno EDOM. (FE_INVALID). : x +1 -1 errno ERANGE ( BUGS). (FE_DIVBYZERO). attributes(7). +------------+------------------------------------+--------------------+ || | | +------------+------------------------------------+--------------------+ |atanh(), | | MT-Safe | |atanhf(), | | | |atanhl() | | | +------------+------------------------------------+--------------------+ C11, POSIX.1-2008. C99 POSIX.1-2001. double SVr4 4.3BSD. glibc 2.9 (pole error) errno EDOM ERANGE POSIX. glibc 2.10 glibc . acosh(3), asinh(3), catanh(3), cosh(3), sinh(3), tanh(3) 3 . . : . 6.18 8 2026 atanh(3)