diff --git a/src/slz.c b/src/slz.c
index 0ca9d279c3..1d6032ea2e 100644
--- a/src/slz.c
+++ b/src/slz.c
@@ -578,6 +578,8 @@ long slz_rfc1951_encode(struct slz_stream *strm, unsigned char *out, const unsig
 		int max_lookup = 2; // 0 = no limit
 
 		for (scan = pos - 1; scan < pos && (unsigned long)(pos - scan - 1) < 32768; scan--) {
+			int len;
+
 			if (*(uint32_t *)(in + scan) != word)
 				continue;