4 files changed, 14 insertions, 9 deletions
diff --git a/zix/common.h b/zix/common.h
index a59c033..f0737eb 100644
--- a/zix/common.h
+++ b/zix/common.h
@@ -52,10 +52,13 @@ extern "C" {
 #    include <stdbool.h>
 #endif
 
-#ifdef __GNUC__
-#define ZIX_UNUSED  __attribute__((__unused__))
+// Unused parameter macro to suppresses warnings and make it impossible to use
+#if defined(__cplusplus)
+#   define ZIX_UNUSED(name)
+#elif defined(__GNUC__)
+#   define ZIX_UNUSED(name) name##_unused __attribute__((__unused__))
 #else
-#define ZIX_UNUSED
+#   define ZIX_UNUSED(name) name
 #endif
 
 typedef enum {
diff --git a/zix/thread.h b/zix/thread.h
index 9f05b10..2af0c5e 100644
--- a/zix/thread.h
+++ b/zix/thread.h
@@ -80,6 +80,8 @@ zix_thread_create(ZixThread* thread,
 static inline ZixStatus
 zix_thread_join(ZixThread thread, void** retval)
 {
+	(void)retval;
+
 	return WaitForSingleObject(thread, INFINITE)
 		? ZIX_STATUS_SUCCESS : ZIX_STATUS_ERROR;
 }
diff --git a/zix/tree.c b/zix/tree.c
index e6698a7..ab23614 100644
--- a/zix/tree.c
+++ b/zix/tree.c
@@ -632,7 +632,7 @@ zix_tree_begin(ZixTree* t)
 }
 
 ZIX_API ZixTreeIter*
-zix_tree_end(ZIX_UNUSED ZixTree* t)
+zix_tree_end(ZixTree* ZIX_UNUSED(t))
 {
 	return NULL;
 }
@@ -652,7 +652,7 @@ zix_tree_rbegin(ZixTree* t)
 }
 
 ZIX_API ZixTreeIter*
-zix_tree_rend(ZIX_UNUSED ZixTree* t)
+zix_tree_rend(ZixTree* ZIX_UNUSED(t))
 {
 	return NULL;
 }
diff --git a/zix/trie.c b/zix/trie.c
index 8a7661c..369b647 100644
--- a/zix/trie.c
+++ b/zix/trie.c
@@ -205,10 +205,10 @@ zix_trie_add_child(ZixTrieNode** n_ptr,
 }
 
 ZIX_PRIVATE ZixTrieNode**
-trie_insert_tail(ZixTrieNode**           n_ptr,
-                 const uint8_t*          str,
-                 const uint8_t*          first,
-                 ZIX_UNUSED const size_t len)
+trie_insert_tail(ZixTrieNode**  n_ptr,
+                 const uint8_t* str,
+                 const uint8_t* first,
+                 const size_t   ZIX_UNUSED(len))
 {
 	assert(first[0]);
 	ZixTrieNode* c = NULL;