pub unsafe extern "C" fn funopen(
__cookie: *const c_void,
__readfn: Option<unsafe extern "C" fn(_: *mut c_void, _: *mut u8, _: i32) -> i32>,
__writefn: Option<unsafe extern "C" fn(_: *mut c_void, _: *const u8, _: 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