--- src/lib/libc/stdio/sprintf.c	2005/07/23 23:14:44	1.6
+++ src/lib/libc/stdio/sprintf.c	2006/03/02 18:05:30	1.7
@@ -60,6 +60,7 @@ sprintf(char *str, char const *fmt, ...)
 	f.fl_mutex = PTHREAD_MUTEX_INITIALIZER;
 	f.fl_owner = NULL;
 	f.fl_count = 0;
+	memset(WCIO_GET(&f), 0, sizeof(struct wchar_io_data));
 	va_start(ap, fmt);
 	ret = __vfprintf(&f, fmt, ap);		/* Use unlocked __vfprintf */
 	va_end(ap);