diff --git a/lib/c-api/src/wasm_c_api/externals/function.rs b/lib/c-api/src/wasm_c_api/externals/function.rs
index 1bffbda29..cf7ff59c7 100644
--- a/lib/c-api/src/wasm_c_api/externals/function.rs
+++ b/lib/c-api/src/wasm_c_api/externals/function.rs
@@ -167,7 +167,7 @@ pub unsafe extern "C" fn wasm_func_call(
                 .expect("Results conversion failed");
 
             // `results` is an uninitialized vector. Set a new value.
-            if results.size == 0 || results.data.is_null() {
+            if results.is_uninitialized() {
                 *results = vals.into();
             }
             // `results` is an initialized but empty vector. Fill it
diff --git a/lib/c-api/src/wasm_c_api/macros.rs b/lib/c-api/src/wasm_c_api/macros.rs
index bbefe8485..77b196ec5 100644
--- a/lib/c-api/src/wasm_c_api/macros.rs
+++ b/lib/c-api/src/wasm_c_api/macros.rs
@@ -56,22 +56,22 @@ macro_rules! wasm_declare_vec {
 
             impl [<wasm_ $name _vec_t>] {
                 pub unsafe fn into_slice(&self) -> Option<&[[<wasm_ $name _t>]]>{
-                    if self.is_unitialized() {
+                    if self.is_uninitialized() {
                         return None;
                     }
 
                     Some(::std::slice::from_raw_parts(self.data, self.size))
                 }
 
-                pub unsafe fn into_slice_mut(&self) -> Option<&mut [[<wasm_ $name _t>]]>{
-                    if self.is_unitialized() {
+                pub unsafe fn into_slice_mut(&mut self) -> Option<&mut [[<wasm_ $name _t>]]>{
+                    if self.is_uninitialized() {
                         return None;
                     }
 
                     Some(::std::slice::from_raw_parts_mut(self.data, self.size))
                 }
 
-                pub fn is_unitialized(&self) -> bool {
+                pub fn is_uninitialized(&self) -> bool {
                     self.data.is_null()
                 }
             }