diff --git a/composer.json b/composer.json
index 466cd52..9f1f5e5 100644
--- a/composer.json
+++ b/composer.json
@@ -13,6 +13,7 @@
         }
     ],
     "require": {
-        "psr/log": "dev-master"
+        "psr/log": "dev-master",
+        "ext-pcntl": "*"
     }
 }