diff --git a/src/c-stdaux/src/test-api.c b/src/c-stdaux/src/test-api.c
index fb500660b0..cddbb70dac 100644
--- a/src/c-stdaux/src/test-api.c
+++ b/src/c-stdaux/src/test-api.c
@@ -11,15 +11,17 @@
 
 static _c_const_ int const_fn(void) { return 0; }
 static _c_deprecated_ _c_unused_ int deprecated_fn(void) { return 0; }
+_c_hidden_ int c_internal_hidden_fn(void);
 _c_hidden_ int c_internal_hidden_fn(void) { return 0; }
-static _c_printf_(1, 2) int printf_fn(const char *f, ...) { return 0; }
+static _c_printf_(1, 2) int printf_fn(const _c_unused_ char *f, ...) { return 0; }
+_c_public_ int c_internal_public_fn(void);
 _c_public_ int c_internal_public_fn(void) { return 0; }
 static _c_pure_ int pure_fn(void) { return 0; }
-static _c_sentinel_ int sentinel_fn(const char *f, ...) { return 0; }
+static _c_sentinel_ int sentinel_fn(const _c_unused_ char *f, ...) { return 0; }
 static _c_unused_ int unused_fn(void) { return 0; }
 
-static void cleanup_fn(int p) {}
-static void direct_cleanup_fn(int p) {}
+static void cleanup_fn(_c_unused_ int p) {}
+static void direct_cleanup_fn(_c_unused_ int p) {}
 C_DEFINE_CLEANUP(int, cleanup_fn);
 C_DEFINE_DIRECT_CLEANUP(int, direct_cleanup_fn);
 
@@ -202,7 +204,7 @@ static void test_api_functions(void) {
                 c_assert(!!fns[i]);
 }
 
-int main(int argc, char **argv) {
+int main(void) {
         test_api_macros();
         test_api_functions();
         return 0;
diff --git a/src/c-stdaux/src/test-basic.c b/src/c-stdaux/src/test-basic.c
index 9549a14303..d58d561d23 100644
--- a/src/c-stdaux/src/test-basic.c
+++ b/src/c-stdaux/src/test-basic.c
@@ -425,7 +425,7 @@ static void test_destructors(void) {
         }
 }
 
-int main(int argc, char **argv) {
+int main(int argc, _c_unused_ char **argv) {
         test_misc(argc);
         test_destructors();
         return 0;