diff --git a/src/core/gpu_vk.c b/src/core/gpu_vk.c
index b9a472de..b96f61d6 100644
--- a/src/core/gpu_vk.c
+++ b/src/core/gpu_vk.c
@@ -63,15 +63,15 @@ struct gpu_stream {
   VkCommandBuffer commands;
 };
 
-size_t gpu_sizeof_buffer() { return sizeof(gpu_buffer); }
-size_t gpu_sizeof_texture() { return sizeof(gpu_texture); }
-size_t gpu_sizeof_sampler() { return sizeof(gpu_sampler); }
-size_t gpu_sizeof_layout() { return sizeof(gpu_layout); }
-size_t gpu_sizeof_shader() { return sizeof(gpu_shader); }
-size_t gpu_sizeof_bundle_pool() { return sizeof(gpu_bundle_pool); }
-size_t gpu_sizeof_bundle() { return sizeof(gpu_bundle); }
-size_t gpu_sizeof_pipeline() { return sizeof(gpu_pipeline); }
-size_t gpu_sizeof_tally() { return sizeof(gpu_tally); }
+size_t gpu_sizeof_buffer(void) { return sizeof(gpu_buffer); }
+size_t gpu_sizeof_texture(void) { return sizeof(gpu_texture); }
+size_t gpu_sizeof_sampler(void) { return sizeof(gpu_sampler); }
+size_t gpu_sizeof_layout(void) { return sizeof(gpu_layout); }
+size_t gpu_sizeof_shader(void) { return sizeof(gpu_shader); }
+size_t gpu_sizeof_bundle_pool(void) { return sizeof(gpu_bundle_pool); }
+size_t gpu_sizeof_bundle(void) { return sizeof(gpu_bundle); }
+size_t gpu_sizeof_pipeline(void) { return sizeof(gpu_pipeline); }
+size_t gpu_sizeof_tally(void) { return sizeof(gpu_tally); }
 
 // Internals
 
@@ -760,7 +760,7 @@ void gpu_texture_destroy(gpu_texture* texture) {
   gpu_release(state.memory + texture->memory);
 }
 
-gpu_texture* gpu_surface_acquire() {
+gpu_texture* gpu_surface_acquire(void) {
   if (!state.surface.valid) {
     return NULL;
   }
@@ -2466,7 +2466,7 @@ void gpu_destroy(void) {
   memset(&state, 0, sizeof(state));
 }
 
-uint32_t gpu_begin() {
+uint32_t gpu_begin(void) {
   gpu_wait_tick(++state.tick[CPU] - COUNTOF(state.ticks));
   gpu_tick* tick = &state.ticks[state.tick[CPU] & TICK_MASK];
   VK(vkResetFences(state.device, 1, &tick->fence), "Fence reset failed") return 0;
@@ -2501,7 +2501,7 @@ void gpu_submit(gpu_stream** streams, uint32_t count) {
   state.surface.semaphore = VK_NULL_HANDLE;
 }
 
-void gpu_present() {
+void gpu_present(void) {
   VkSemaphore semaphore = state.ticks[state.tick[CPU] & TICK_MASK].semaphores[1];
 
   VkSubmitInfo submit = {
@@ -2547,19 +2547,19 @@ bool gpu_wait_tick(uint32_t tick) {
   }
 }
 
-void gpu_wait_idle() {
+void gpu_wait_idle(void) {
   vkDeviceWaitIdle(state.device);
 }
 
-uintptr_t gpu_vk_get_instance() {
+uintptr_t gpu_vk_get_instance(void) {
   return (uintptr_t) state.instance;
 }
 
-uintptr_t gpu_vk_get_physical_device() {
+uintptr_t gpu_vk_get_physical_device(void) {
   return (uintptr_t) state.adapter;
 }
 
-uintptr_t gpu_vk_get_device() {
+uintptr_t gpu_vk_get_device(void) {
   return (uintptr_t) state.device;
 }
 
diff --git a/src/modules/filesystem/filesystem.c b/src/modules/filesystem/filesystem.c
index 3a88e5aa..1d6136b4 100644
--- a/src/modules/filesystem/filesystem.c
+++ b/src/modules/filesystem/filesystem.c
@@ -174,7 +174,7 @@ bool lovrFilesystemInit(const char* archive) {
   return true;
 }
 
-void lovrFilesystemDestroy() {
+void lovrFilesystemDestroy(void) {
   if (!state.initialized) return;
   for (size_t i = 0; i < state.archives.length; i++) {
     Archive* archive = &state.archives.data[i];
@@ -184,11 +184,11 @@ void lovrFilesystemDestroy() {
   memset(&state, 0, sizeof(state));
 }
 
-const char* lovrFilesystemGetSource() {
+const char* lovrFilesystemGetSource(void) {
   return state.source;
 }
 
-bool lovrFilesystemIsFused() {
+bool lovrFilesystemIsFused(void) {
   return state.fused;
 }
 
@@ -309,7 +309,7 @@ void lovrFilesystemGetDirectoryItems(const char* path, void (*callback)(void* co
 
 // Writing
 
-const char* lovrFilesystemGetIdentity() {
+const char* lovrFilesystemGetIdentity(void) {
   return state.identity[0] == '\0' ? NULL : state.identity;
 }
 
@@ -361,7 +361,7 @@ bool lovrFilesystemSetIdentity(const char* identity, bool precedence) {
   return true;
 }
 
-const char* lovrFilesystemGetSaveDirectory() {
+const char* lovrFilesystemGetSaveDirectory(void) {
   return state.savePath;
 }
 
@@ -428,7 +428,7 @@ size_t lovrFilesystemGetWorkingDirectory(char* buffer, size_t size) {
   return os_get_working_directory(buffer, size);
 }
 
-const char* lovrFilesystemGetRequirePath() {
+const char* lovrFilesystemGetRequirePath(void) {
   return state.requirePath;
 }
 
diff --git a/src/modules/headset/headset.c b/src/modules/headset/headset.c
index 40cc0c1f..9985311f 100644
--- a/src/modules/headset/headset.c
+++ b/src/modules/headset/headset.c
@@ -34,7 +34,7 @@ bool lovrHeadsetInit(HeadsetConfig* config) {
   return true;
 }
 
-void lovrHeadsetDestroy() {
+void lovrHeadsetDestroy(void) {
   if (!initialized) return;
   initialized = false;
   if (lovrHeadsetInterface) {
diff --git a/src/modules/physics/physics.c b/src/modules/physics/physics.c
index 04eebb6b..3d0ea89e 100644
--- a/src/modules/physics/physics.c
+++ b/src/modules/physics/physics.c
@@ -109,7 +109,7 @@ static void onInfoMessage(int num, const char* format, va_list args) {
 
 static bool initialized = false;
 
-bool lovrPhysicsInit() {
+bool lovrPhysicsInit(void) {
   if (initialized) return false;
   dInitODE();
   dSetErrorHandler(onErrorMessage);
@@ -118,7 +118,7 @@ bool lovrPhysicsInit() {
   return initialized = true;
 }
 
-void lovrPhysicsDestroy() {
+void lovrPhysicsDestroy(void) {
   if (!initialized) return;
   dCloseODE();
   initialized = false;
diff --git a/src/modules/system/system.c b/src/modules/system/system.c
index 0843c4ae..1b8b1006 100644
--- a/src/modules/system/system.c
+++ b/src/modules/system/system.c
@@ -69,7 +69,7 @@ static void onQuit(void) {
   });
 }
 
-bool lovrSystemInit() {
+bool lovrSystemInit(void) {
   if (state.initialized) return false;
   os_on_key(onKey);
   os_on_text(onText);
@@ -89,11 +89,11 @@ void lovrSystemDestroy() {
   memset(&state, 0, sizeof(state));
 }
 
-const char* lovrSystemGetOS() {
+const char* lovrSystemGetOS(void) {
   return os_get_name();
 }
 
-uint32_t lovrSystemGetCoreCount() {
+uint32_t lovrSystemGetCoreCount(void) {
   return os_get_core_count();
 }
 
@@ -110,7 +110,7 @@ void lovrSystemOpenWindow(os_window_config* window) {
   os_on_quit(onQuit);
 }
 
-bool lovrSystemIsWindowOpen() {
+bool lovrSystemIsWindowOpen(void) {
   return os_window_is_open();
 }
 
@@ -118,7 +118,7 @@ void lovrSystemGetWindowSize(uint32_t* width, uint32_t* height) {
   os_window_get_size(width, height);
 }
 
-float lovrSystemGetWindowDensity() {
+float lovrSystemGetWindowDensity(void) {
   return os_window_get_pixel_density();
 }
 
diff --git a/src/modules/thread/thread.c b/src/modules/thread/thread.c
index f6ae887c..13385523 100644
--- a/src/modules/thread/thread.c
+++ b/src/modules/thread/thread.c
@@ -36,14 +36,14 @@ static struct {
   map_t channels;
 } state;
 
-bool lovrThreadModuleInit() {
+bool lovrThreadModuleInit(void) {
   if (state.initialized) return false;
   mtx_init(&state.channelLock, mtx_plain);
   map_init(&state.channels, 0);
   return state.initialized = true;
 }
 
-void lovrThreadModuleDestroy() {
+void lovrThreadModuleDestroy(void) {
   if (!state.initialized) return;
   for (size_t i = 0; i < state.channels.size; i++) {
     if (state.channels.values[i] != MAP_NIL) {
diff --git a/src/modules/timer/timer.c b/src/modules/timer/timer.c
index 64a5687c..bfa6fc73 100644
--- a/src/modules/timer/timer.c
+++ b/src/modules/timer/timer.c
@@ -13,27 +13,27 @@ static struct {
   double tickBuffer[TICK_SAMPLES];
 } state;
 
-bool lovrTimerInit() {
+bool lovrTimerInit(void) {
   if (state.initialized) return false;
   state.initialized = true;
   state.epoch = os_get_time();
   return true;
 }
 
-void lovrTimerDestroy() {
+void lovrTimerDestroy(void) {
   if (!state.initialized) return;
   memset(&state, 0, sizeof(state));
 }
 
-double lovrTimerGetDelta() {
+double lovrTimerGetDelta(void) {
   return state.dt;
 }
 
-double lovrTimerGetTime() {
+double lovrTimerGetTime(void) {
   return os_get_time() - state.epoch;
 }
 
-double lovrTimerStep() {
+double lovrTimerStep(void) {
   state.lastTime = state.time;
   state.time = os_get_time();
   state.dt = state.time - state.lastTime;
@@ -46,11 +46,11 @@ double lovrTimerStep() {
   return state.dt;
 }
 
-double lovrTimerGetAverageDelta() {
+double lovrTimerGetAverageDelta(void) {
   return state.tickSum / TICK_SAMPLES;
 }
 
-int lovrTimerGetFPS() {
+int lovrTimerGetFPS(void) {
   return (int) (1 / (state.tickSum / TICK_SAMPLES) + .5);
 }