— Function: double gsl_sf_bessel_zero_J0 (unsigned int s)
— Function: int gsl_sf_bessel_zero_J0_e (unsigned int s, gsl_sf_result * result)

These routines compute the location of the s-th positive zero of the Bessel function J_0(x).

— Function: double gsl_sf_bessel_zero_J1 (unsigned int s)
— Function: int gsl_sf_bessel_zero_J1_e (unsigned int s, gsl_sf_result * result)

These routines compute the location of the s-th positive zero of the Bessel function J_1(x).

— Function: double gsl_sf_bessel_zero_Jnu (double nu, unsigned int s)
— Function: int gsl_sf_bessel_zero_Jnu_e (double nu, unsigned int s, gsl_sf_result * result)

These routines compute the location of the s-th positive zero of the Bessel function J_\nu(x). The current implementation does not support negative values of nu.