diff --git a/src/core/Curl/Handler.php b/src/core/Curl/Handler.php
index 5f68bc9..858342a 100644
--- a/src/core/Curl/Handler.php
+++ b/src/core/Curl/Handler.php
@@ -176,14 +176,14 @@ public function getInfo()
         return $this->isAvailable() ? $this->info : false;
     }
 
-    public function errno()
+    public function errno(): int
     {
-        return $this->isAvailable() ? $this->errCode : false;
+        return $this->isAvailable() ? $this->errCode : 0;
     }
 
-    public function error()
+    public function error(): string
     {
-        return $this->isAvailable() ? $this->errMsg : false;
+        return $this->isAvailable() ? $this->errMsg : '';
     }
 
     public function reset()
diff --git a/src/ext/curl.php b/src/ext/curl.php
index afeb990..e1f2eef 100644
--- a/src/ext/curl.php
+++ b/src/ext/curl.php
@@ -60,12 +60,12 @@ function swoole_curl_getinfo(Swoole\Curl\Handler $obj, int $opt = 0)
     return $info;
 }
 
-function swoole_curl_errno(Swoole\Curl\Handler $obj)
+function swoole_curl_errno(Swoole\Curl\Handler $obj): int
 {
     return $obj->errno();
 }
 
-function swoole_curl_error(Swoole\Curl\Handler $obj)
+function swoole_curl_error(Swoole\Curl\Handler $obj): string
 {
     return $obj->error();
 }
@@ -75,9 +75,9 @@ function swoole_curl_reset(Swoole\Curl\Handler $obj)
     return $obj->reset();
 }
 
-function swoole_curl_close(Swoole\Curl\Handler $obj)
+function swoole_curl_close(Swoole\Curl\Handler $obj): void
 {
-    return $obj->close();
+    $obj->close();
 }
 
 function swoole_curl_multi_getcontent(Swoole\Curl\Handler $obj)