Index: uspace/lib/c/generic/io/io.c
===================================================================
--- uspace/lib/c/generic/io/io.c	(revision fb4a424279571d50c7676c2c88d543bdf1bf68b7)
+++ uspace/lib/c/generic/io/io.c	(revision 5b1813795d41cbb726ef1c77c6a223085a955fd0)
@@ -271,4 +271,5 @@
 	stream->need_sync = false;
 	_setvbuf(stream);
+	stream->ungetc_chars = 0;
 	
 	list_append(&stream->link, &files);
@@ -293,4 +294,5 @@
 	stream->need_sync = false;
 	_setvbuf(stream);
+	stream->ungetc_chars = 0;
 	
 	list_append(&stream->link, &files);