pub unsafe extern "C" fn funopen(
__cookie: *const c_void,
__readfn: Option<unsafe extern "C" fn(*mut c_void, *mut i8, i32) -> i32>,
__writefn: Option<unsafe extern "C" fn(*mut c_void, *const i8, i32) -> i32>,
__seekfn: Option<unsafe extern "C" fn(*mut c_void, i32, i32) -> i32>,
__closefn: Option<unsafe extern "C" fn(*mut c_void) -> i32>
) -> *mut __sFILE