diff --git a/libavformat/avio.h b/libavformat/avio.h
index d7b7e2630d94a4fc6675fbd44ed669b294a02d60..fbc418ed580e9a85e00742e724022f19bd98861c 100644
--- a/libavformat/avio.h
+++ b/libavformat/avio.h
@@ -103,7 +103,16 @@ int url_read(URLContext *h, unsigned char *buf, int size);
 int url_read_complete(URLContext *h, unsigned char *buf, int size);
 int url_write(URLContext *h, unsigned char *buf, int size);
 int64_t url_seek(URLContext *h, int64_t pos, int whence);
+
+/**
+ * Closes the resource accessed by the URLContext h, and frees the
+ * memory used by it.
+ *
+ * @return a negative value if an error condition occurred, 0
+ * otherwise
+ */
 int url_close(URLContext *h);
+
 int url_exist(const char *filename);
 int64_t url_filesize(URLContext *h);