diff --git a/src/Symfony/Component/Console/Output/StreamOutput.php b/src/Symfony/Component/Console/Output/StreamOutput.php
index 7ff602763e9da..e1b8c9ca5437a 100644
--- a/src/Symfony/Component/Console/Output/StreamOutput.php
+++ b/src/Symfony/Component/Console/Output/StreamOutput.php
@@ -74,10 +74,10 @@ protected function doWrite($message, $newline)
             $message .= PHP_EOL;
         }
 
-        if (false === @fwrite($this->stream, $message)) {
-            // should never happen
+        if (!is_resource($this->stream) || !is_string($message)) {
             throw new RuntimeException('Unable to write output.');
         }
+        @fwrite($this->stream, $message);
 
         fflush($this->stream);
     }