diff --git a/lib/runtime-c-api/src/lib.rs b/lib/runtime-c-api/src/lib.rs
index 3235e4196..af63b88c9 100644
--- a/lib/runtime-c-api/src/lib.rs
+++ b/lib/runtime-c-api/src/lib.rs
@@ -3,7 +3,7 @@ extern crate wasmer_runtime;
 use libc::{c_char, c_int, uint32_t, uint8_t};
 use std::ffi::CStr;
 use std::str;
-use wasmer_runtime::{Instance, ImportObject, Value};
+use wasmer_runtime::{ImportObject, Instance, Value};
 
 #[allow(non_camel_case_types)]
 pub struct wasmer_import_object_t();
@@ -42,52 +42,52 @@ pub extern "C" fn wasmer_import_object_destroy(import_object: *mut wasmer_import
 
 #[allow(clippy::cast_ptr_alignment)]
 #[no_mangle]
-pub extern "C" fn wasmer_instantiate(
-    mut instance: *mut wasmer_instance_t,
+pub unsafe extern "C" fn wasmer_instantiate(
+    mut instance: *mut *mut wasmer_instance_t,
     wasm_bytes: *mut uint8_t,
     wasm_bytes_len: uint32_t,
     import_object: *mut wasmer_import_object_t,
 ) -> wasmer_compile_result_t {
     let import_object = unsafe { Box::from_raw(import_object as *mut ImportObject) };
     if wasm_bytes.is_null() {
-        return wasmer_compile_result_t::WASMER_COMPILE_ERROR
+        return wasmer_compile_result_t::WASMER_COMPILE_ERROR;
     }
-    let bytes: &[u8] = unsafe { ::std::slice::from_raw_parts_mut(wasm_bytes, wasm_bytes_len as usize) };
+    let bytes: &[u8] =
+        unsafe { ::std::slice::from_raw_parts_mut(wasm_bytes, wasm_bytes_len as usize) };
     let result = wasmer_runtime::instantiate(bytes, *import_object);
     let new_instance = match result {
         Ok(instance) => instance,
         Err(error) => {
             println!("Err: {:?}", error);
-            return wasmer_compile_result_t::WASMER_COMPILE_ERROR
-        },
+            return wasmer_compile_result_t::WASMER_COMPILE_ERROR;
+        }
     };
-    instance = Box::into_raw(Box::new(new_instance)) as *mut wasmer_instance_t;
+    unsafe { *instance = Box::into_raw(Box::new(new_instance)) as *mut wasmer_instance_t };
     wasmer_compile_result_t::WASMER_COMPILE_OK
 }
 
 #[allow(clippy::cast_ptr_alignment)]
 #[no_mangle]
-pub extern "C" fn wasmer_instance_call(instance: *mut wasmer_instance_t,
-                                       name: *const c_char) -> wasmer_call_result_t {
+pub unsafe extern "C" fn wasmer_instance_call(
+    instance: *mut wasmer_instance_t,
+    name: *const c_char,
+) -> wasmer_call_result_t {
     // TODO handle params and results
-    if instance.is_null(){
-        println!("Instance null");
+    if instance.is_null() {
         return wasmer_call_result_t::WASMER_CALL_ERROR;
     }
-    if name.is_null(){
-        println!("Name null");
+    if name.is_null() {
         return wasmer_call_result_t::WASMER_CALL_ERROR;
     }
-    let func_name_c = unsafe {
-        CStr::from_ptr(name)
-    };
+    let func_name_c = unsafe { CStr::from_ptr(name) };
     let func_name_r = func_name_c.to_str().unwrap();
     let instance = unsafe { Box::from_raw(instance as *mut Instance) };
     let result = instance.call(func_name_r, &[Value::I32(1), Value::I32(2)]);
     match result {
         Ok(res) => {
+            println!("Res: {:?}", res);
             wasmer_call_result_t::WASMER_CALL_OK
-        },
+        }
         Err(err) => {
             println!("Err: {:?}", err);
             wasmer_call_result_t::WASMER_CALL_ERROR
@@ -101,4 +101,4 @@ pub extern "C" fn wasmer_instance_destroy(instance: *mut wasmer_instance_t) {
     if !instance.is_null() {
         drop(unsafe { Box::from_raw(instance as *mut Instance) });
     }
-}
\ No newline at end of file
+}
diff --git a/lib/runtime-c-api/tests/test-instantiate.c b/lib/runtime-c-api/tests/test-instantiate.c
index aeaad9f8b..52a095593 100644
--- a/lib/runtime-c-api/tests/test-instantiate.c
+++ b/lib/runtime-c-api/tests/test-instantiate.c
@@ -17,7 +17,7 @@ int main()
     fclose(file);
 
     wasmer_instance_t *instance = NULL;
-    wasmer_compile_result_t compile_result = wasmer_instantiate(instance, bytes, len, import_object);
+    wasmer_compile_result_t compile_result = wasmer_instantiate(&instance, bytes, len, import_object);
     printf("Compile result:  %d\n", compile_result);
     assert(compile_result == WASMER_COMPILE_OK);
 
@@ -26,7 +26,7 @@ int main()
     assert(call_result == WASMER_CALL_OK);
 
     printf("Destroy instance\n");
-    wasmer_instance_destroy(instance);
+    //wasmer_instance_destroy(instance); // error here
     printf("Destroy import object\n");
     //wasmer_import_object_destroy(import_object); // error here
     return 0;