From cf11c789d1cc2d56b27413899570670cf1a53395 Mon Sep 17 00:00:00 2001
From: Yifan Wu <shinbokuow@163.com>
Date: Sat, 30 Jan 2021 01:24:58 +0800
Subject: [PATCH] Declare _unused explicitly when running first task.

---
 os/src/task/mod.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/os/src/task/mod.rs b/os/src/task/mod.rs
index 8d739ca9..24062bee 100644
--- a/os/src/task/mod.rs
+++ b/os/src/task/mod.rs
@@ -48,9 +48,10 @@ impl TaskManager {
     fn run_first_task(&self) {
         self.inner.borrow_mut().tasks[0].task_status = TaskStatus::Running;
         let next_task_cx_ptr2 = self.inner.borrow().tasks[0].get_task_cx_ptr2();
+        let _unused: usize = 0;
         unsafe {
             __switch(
-                &0usize as *const _,
+                &_unused as *const _,
                 next_task_cx_ptr2,
             );
         }