diff --git a/expat/fuzz/xml_parse_fuzzer.c b/expat/fuzz/xml_parse_fuzzer.c
index 8b52c7f3..48b50212 100644
--- a/expat/fuzz/xml_parse_fuzzer.c
+++ b/expat/fuzz/xml_parse_fuzzer.c
@@ -37,9 +37,14 @@ static unsigned char hash_key[16] = "FUZZING IS FUN!";
 
 static void XMLCALL
 start(void *userData, const XML_Char *name, const XML_Char **atts) {
+  (void)userData;
+  (void)name;
+  (void)atts;
 }
 static void XMLCALL
 end(void *userData, const XML_Char *name) {
+  (void)userData;
+  (void)name;
 }
 
 int
diff --git a/expat/fuzz/xml_parsebuffer_fuzzer.c b/expat/fuzz/xml_parsebuffer_fuzzer.c
index 3f0d7a59..0c7a8f2b 100644
--- a/expat/fuzz/xml_parsebuffer_fuzzer.c
+++ b/expat/fuzz/xml_parsebuffer_fuzzer.c
@@ -38,9 +38,14 @@ static unsigned char hash_key[16] = "FUZZING IS FUN!";
 
 static void XMLCALL
 start(void *userData, const XML_Char *name, const XML_Char **atts) {
+  (void)userData;
+  (void)name;
+  (void)atts;
 }
 static void XMLCALL
 end(void *userData, const XML_Char *name) {
+  (void)userData;
+  (void)name;
 }
 
 int