cpp/numeric/special functions/comp ellint 3

@1-3@ Computes the of the arguments  and. @A@ Additional overloads are provided for all other combinations of arithmetic types.

Return value
If no errors occur, value of the complete elliptic integral of the third kind of and, that is , is returned.

Error handling
Errors may be reported as specified in math_errhandling.
 * If the argument is NaN, NaN is returned and domain error is not reported
 * If $|k|>1$, a domain error may occur