resolves issue #18

src/Drivers/Cookie.php

@@ -16,6 +16,7 @@ public function close(): bool
         return true;
     }
 
+    #[\ReturnTypeWillChange]
     public function read($id): string
     {
         return $this->get($_COOKIE[$id] ?? '');
@@ -36,8 +37,9 @@ public function destroy($id): bool
         return true;
     }
 
-    public function gc($max_lifetime): bool
+    #[\ReturnTypeWillChange]
+    public function gc($max_lifetime)
     {
-        return true;
+        return 0;
     }
 }

src/Drivers/File.php

@@ -20,6 +20,7 @@ public function close(): bool
         return true;
     }
 
+    #[\ReturnTypeWillChange]
     public function read($id): string
     {
         return $this->get((string) @file_get_contents("{$this->save_path}/sess_{$id}"));
@@ -39,15 +40,19 @@ public function destroy($id): bool
         return true;
     }
 
-    public function gc($max_lifetime): bool
+    #[\ReturnTypeWillChange]
+    public function gc($max_lifetime)
     {
         $time = time();
+        $count = 0;
+
         foreach (glob("{$this->save_path}sess_*") as $file) {
             if (filemtime($file) + $max_lifetime < $time && file_exists($file)) {
                 unlink($file);
+                $count++;
             }
         }
 
-        return true;
+        return $count;
     }
 }

src/Drivers/Memcached.php

@@ -41,6 +41,7 @@ public function close(): bool
         return true;
     }
 
+    #[\ReturnTypeWillChange]
     public function read($id): string
     {
         return $this->get($this->conn->get("{$this->name}{$id}") ?: '');
@@ -56,8 +57,9 @@ public function destroy($id): bool
         return $this->conn->delete("{$this->name}{$id}");
     }
 
-    public function gc($max_lifetime): bool
+    #[\ReturnTypeWillChange]
+    public function gc($max_lifetime)
     {
-        return true;
+        return 0;
     }
 }

src/Drivers/MySql.php

@@ -86,14 +86,16 @@ public function destroy($id): bool
         return $completed;
     }
 
-    public function gc($max_lifetime): bool
+    #[\ReturnTypeWillChange]
+    public function gc($max_lifetime)
     {
         $max_lifetime = time() - $max_lifetime;
         $statement    = $this->conn->prepare("DELETE FROM `{$this->table}` WHERE `time` < :time");
         $statement->bindParam(':time', $max_lifetime, PDO::PARAM_INT);
-        $completed = $statement->execute();
+        $statement->execute();
+        $count = $statement->rowCount();
         $statement = null; // close
 
-        return $completed;
+        return $count;
     }
 }

src/Drivers/Redis.php

@@ -34,6 +34,7 @@ public function close(): bool
         return true;
     }
 
+    #[\ReturnTypeWillChange]
     public function read($id): string
     {
         return $this->get($this->conn->get("{$this->name}{$id}") ?: '');
@@ -49,8 +50,9 @@ public function destroy($id): bool
         return $this->conn->del("{$this->name}{$id}") > 0;
     }
 
-    public function gc($max_lifetime): bool
+    #[\ReturnTypeWillChange]
+    public function gc($max_lifetime)
     {
-        return true;
+        return 0;
     }
 }

src/default_config.php

@@ -19,7 +19,8 @@
         'cookie_lifetime'   => '0',                 # Specifies the lifetime of the cookie in seconds which is sent to the browser. The value 0 means "until the browser is closed."
         'gc_maxlifetime'    => '1440',              # Specifies the number of seconds after which data will be seen as 'garbage' and potentially cleaned up.
         'use_strict_mode'   => '1',                 # Specifies whether the module will use strict session id mode.
-        'gc_probability'    => '1',                 #
+        'gc_probability'    => '1',                 # https://www.php.net/manual/en/session.configuration.php#ini.session.gc-probability
+        'gc_divisor'        => '100',               # https://www.php.net/manual/en/session.configuration.php#ini.session.gc-divisor
     ],
 
     Session::CONFIG_MYSQL_DS         => [