### Hyperbolic Integrals

Function: double gsl_sf_Shi (double x)
Function: int gsl_sf_Shi_e (double x, gsl_sf_result * result)
  These routines compute the integral Shi(x) = \int_0^x dt \sinh(t)/t.

Function: double gsl_sf_Chi (double x)
Function: int gsl_sf_Chi_e (double x, gsl_sf_result * result)
  These routines compute the integral Chi(x) := Re[ \gamma_E + \log(x) + \int_0^x dt (\cosh[t]-1)/t] , where \gamma_E is the Euler constant (available as the macro `M_EULER`).