Function esp_idf_sys::funopen

pub unsafe extern "C" fn funopen(
    __cookie: *const c_void,
    __readfn: Option<unsafe extern "C" fn(__cookie: *mut c_void, __buf: *mut c_char, __n: c_int) -> c_int>,
    __writefn: Option<unsafe extern "C" fn(__cookie: *mut c_void, __buf: *const c_char, __n: c_int) -> c_int>,
    __seekfn: Option<unsafe extern "C" fn(__cookie: *mut c_void, __off: fpos_t, __whence: c_int) -> fpos_t>,
    __closefn: Option<unsafe extern "C" fn(__cookie: *mut c_void) -> c_int>
) -> *mut FILE