Function onig_sys::onig_foreach_name

pub unsafe extern "C" fn onig_foreach_name(
    reg: OnigRegex, 
    func: Option<unsafe extern "C" fn(arg1: *const OnigUChar, arg2: *const OnigUChar, arg3: c_int, arg4: *mut c_int, arg5: OnigRegex, arg6: *mut c_void) -> c_int>, 
    arg: *mut c_void
) -> c_int