diff --git a/vlib/sync/mutex_test.v b/vlib/sync/mutex_test.v
index 42bbffa948..3075024e4b 100644
--- a/vlib/sync/mutex_test.v
+++ b/vlib/sync/mutex_test.v
@@ -35,8 +35,8 @@ fn test_try_lock_mutex() {
 	try_fail := mx.try_lock()
 	assert try_fail == false
 	mx.unlock()
-	try_sucess := mx.try_lock()
-	assert try_sucess == true
-	mx.unlock() // you must unlock it, after try_lock sucess
+	try_success := mx.try_lock()
+	assert try_success == true
+	mx.unlock() // you must unlock it, after try_lock success
 	mx.destroy()
 }
diff --git a/vlib/sync/rwmutex_test.v b/vlib/sync/rwmutex_test.v
index b860b98dbb..e9b145db2b 100644
--- a/vlib/sync/rwmutex_test.v
+++ b/vlib/sync/rwmutex_test.v
@@ -51,12 +51,12 @@ fn test_try_lock_rwmutex() {
 
 	mx.unlock()
 
-	// try_rlock will always sucess when mx unlocked,
+	// try_rlock will always succeed when mx unlocked,
 	// multiple try_rlock can apply to the same mx
-	try_sucess_reading2 := mx.try_rlock()
-	try_sucess_reading3 := mx.try_rlock()
-	assert try_sucess_reading2 == true
-	assert try_sucess_reading3 == true
+	try_success_reading2 := mx.try_rlock()
+	try_success_reading3 := mx.try_rlock()
+	assert try_success_reading2 == true
+	assert try_success_reading3 == true
 
 	// if mx is rlocked, then the try_wlock will fail
 	try_fail_writing2 := mx.try_wlock()
@@ -65,10 +65,10 @@ fn test_try_lock_rwmutex() {
 	mx.runlock()
 	mx.runlock() // you must release rlock mutiple times, as it was rlocked multiple times
 
-	// after mx release all rlock, try_wlock will sucess
-	try_sucess_writing3 := mx.try_wlock()
-	assert try_sucess_writing3 == true
+	// after mx release all rlock, try_wlock will succeed
+	try_success_writing3 := mx.try_wlock()
+	assert try_success_writing3 == true
 
-	mx.unlock() // you must unlock it, after try_wlock sucess
+	mx.unlock() // you must unlock it, after try_wlock success
 	mx.destroy()
 }
diff --git a/vlib/sync/sync_freebsd.c.v b/vlib/sync/sync_freebsd.c.v
index f8a008dec3..99d9a3e9a5 100644
--- a/vlib/sync/sync_freebsd.c.v
+++ b/vlib/sync/sync_freebsd.c.v
@@ -41,22 +41,25 @@ pub struct C.pthread_mutex {}
 
 pub struct C.pthread_rwlock {}
 
-pub struct C.pthread_rwlockattr {}
+@[typedef]
+pub struct C.pthread_rwlockattr_t {}
 
 @[typedef]
 pub struct C.sem_t {}
 
 // [init_with=new_mutex] // TODO: implement support for this struct attribute, and disallow Mutex{} from outside the sync.new_mutex() function.
+@[heap]
 pub struct Mutex {
 	mutex &C.pthread_mutex = unsafe { nil }
 }
 
+@[heap]
 pub struct RwMutex {
 	mutex &C.pthread_rwlock = unsafe { nil }
 }
 
 struct RwMutexAttr {
-	attr &C.pthread_rwlockattr = unsafe { nil }
+	attr C.pthread_rwlockattr_t
 }
 
 @[heap]