As per C11 DR#471, ctanh (0 + i NaN) and ctanh (0 + i Inf) should return
0 + i NaN (with "invalid" exception in the second case). This has
corresponding implications for ctan(z), as its errors and special cases
are handled as if the operation is implemented by -i*ctanh(i*z).
This patch fixes cmath's code to do same.
Glibs patch: https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=d15e83c5f5231d971472b5ffc9219d54056ca0f1
As per C11 DR#471 (adjusted resolution accepted for C17), cacosh (0 +
iNaN) should return NaN ± i pi/2, not NaN + iNaN. This patch
fixes cmath's code to do same.
algonell
Sergey B Kirpichev
Nikita Sobolev