Function z3_sys::Z3_solver_get_reason_unknown

pub unsafe extern "C" fn Z3_solver_get_reason_unknown(
    c: Z3_context, 
    s: Z3_solver
) -> Z3_string

Return a brief justification for an “unknown” result (i.e., Z3_L_UNDEF) for the commands Z3_solver_check and Z3_solver_check_assumptions