diff --git a/flattree.c b/flattree.c
index a26e71b..5889900 100644
--- a/flattree.c
+++ b/flattree.c
@@ -136,7 +136,7 @@ static void asm_emit_cell(void *e, cell_t val)
 static void asm_emit_string(void *e, char *str, int len)
 {
 	FILE *f = e;
-	char c;
+	char c = 0;
 
 	if (len != 0) {
 		/* XXX: ewww */