* for those nested protocols.
*/
int (*url_open2)(URLContext *h, const char *url, int flags, AVDictionary **options);
+
+ /**
+ * Read data from the protocol.
+ * If data is immediately available (even less than size), EOF is
+ * reached or an error occurs (including EINTR), return immediately.
+ * Otherwise:
+ * In non-blocking mode, return AVERROR(EAGAIN) immediately.
+ * In blocking mode, wait for data/EOF/error with a short timeout (0.1s),
+ * and return AVERROR(EAGAIN) on timeout.
+ * Checking interrupt_callback, looping on EINTR and EAGAIN and until
+ * enough data has been read is left to the calling function; see
+ * retry_transfer_wrapper in avio.c.
+ */
int (*url_read)( URLContext *h, unsigned char *buf, int size);
int (*url_write)(URLContext *h, const unsigned char *buf, int size);
int64_t (*url_seek)( URLContext *h, int64_t pos, int whence);