Doxument url_fdopen().

Originally committed as revision 21647 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/avio.h

@@ -381,8 +381,17 @@ static inline int url_is_streamed(ByteIOContext *s)
     return s->is_streamed;
 }
 
-/** @note when opened as read/write, the buffers are only used for
-    writing */
+/**
+ * Creates and initializes a ByteIOContext for accessing the
+ * resource referenced by the URLContext h.
+ * @note When the URLContext h has been opened in read+write mode, the
+ * ByteIOContext can be used only for writing.
+ *
+ * @param s Used to return the pointer to the created ByteIOContext.
+ * In case of failure the pointed to value is set to NULL.
+ * @return 0 in case of success, a negative value corresponding to an
+ * AVERROR code in case of failure
+ */
 int url_fdopen(ByteIOContext **s, URLContext *h);
 
 /** @warning must be called before any I/O */