diff --git a/main.c b/main.c
index 2f2dade..b6a2751 100644
--- a/main.c
+++ b/main.c
@@ -6,7 +6,7 @@
 #include "test_gc.h"
 #include "vm.h"
 
-void test_int_alloc() {
+void test_int_alloc(void) {
   struct virtualMachine *vm = initVM();
   pushInt(vm, 100);
   pushInt(vm, 1000);
@@ -18,7 +18,7 @@ void test_int_alloc() {
   free(vm);
 }
 
-void test_pair_alloc() {
+void test_pair_alloc(void) {
   struct virtualMachine *vm = initVM();
   pushInt(vm, 100);
   pushInt(vm, 1000);
@@ -32,7 +32,7 @@ void test_pair_alloc() {
   free(vm);
 }
 
-void test_obj_count() {
+void test_obj_count(void) {
   struct virtualMachine *vm = initVM();
   pushInt(vm, 100);
   pushInt(vm, 1000);
@@ -45,7 +45,7 @@ void test_obj_count() {
   free(vm);
 }
 
-void test_nested_pair() {
+void test_nested_pair(void) {
   struct virtualMachine *vm = initVM();
   pushInt(vm, 100);
   pushInt(vm, 1000);
@@ -61,7 +61,7 @@ void test_nested_pair() {
   free(vm);
 }
 
-void test_unreachable() {
+void test_unreachable(void) {
   struct virtualMachine *vm = initVM();
   pushInt(vm, 100);
   pushInt(vm, 1000);
@@ -74,7 +74,7 @@ void test_unreachable() {
   free(vm);
 }
 
-void test_auto_gc() {
+void test_auto_gc(void) {
   struct virtualMachine *vm = initVM();
 
   for (size_t i = 0; i < 505; ++i) {
diff --git a/vm.h b/vm.h
index 8e7f0bc..445ef6a 100644
--- a/vm.h
+++ b/vm.h
@@ -40,7 +40,7 @@ struct garbageObject *initGarbage(struct virtualMachine *vm,
                                   enum garbageData type);
 
 // Create a new VM
-struct virtualMachine *initVM();
+struct virtualMachine *initVM(void);
 
 // Generic function to push data onto the VM stack
 void push(struct virtualMachine *vm, struct garbageObject *value);