diff --git a/lib/gpio/source/Pin.php b/lib/gpio/source/Pin.php
index 6e5fb4a..7403885 100755
--- a/lib/gpio/source/Pin.php
+++ b/lib/gpio/source/Pin.php
@@ -15,7 +15,7 @@
 		private $value;
 
 		public function __construct($pin){
-			if( !is_int($pin) )
+			if( !preg_match('@^\d+$@', $pin) )
 				throw new Exception("pin must be an integer");
 
 
diff --git a/lib/gpio/source/high.php b/lib/gpio/source/high.php
index 6f6790b..45e6fe1 100755
--- a/lib/gpio/source/high.php
+++ b/lib/gpio/source/high.php
@@ -22,6 +22,8 @@
 		/* (2) Set mode to in */
 		$gpio->value = Pin::GPIO_HIGH;
 
+		return 0;
+
 	}
 
 
diff --git a/lib/gpio/source/in.php b/lib/gpio/source/in.php
index 4a74ccf..7dca599 100755
--- a/lib/gpio/source/in.php
+++ b/lib/gpio/source/in.php
@@ -22,6 +22,8 @@
 		/* (2) Set mode to in */
 		$gpio->mode = Pin::GPIO_IN;
 
+		return 0;
+
 	}
 
 
diff --git a/lib/gpio/source/low.php b/lib/gpio/source/low.php
index 552bc91..3ab526d 100755
--- a/lib/gpio/source/low.php
+++ b/lib/gpio/source/low.php
@@ -22,6 +22,8 @@
 		/* (2) Set mode to in */
 		$gpio->value = Pin::GPIO_LOW;
 
+		return 0;
+
 	}
 
 
diff --git a/lib/gpio/source/out.php b/lib/gpio/source/out.php
index 087bb2b..3909207 100755
--- a/lib/gpio/source/out.php
+++ b/lib/gpio/source/out.php
@@ -22,6 +22,8 @@
 		/* (2) Set mode to in */
 		$gpio->mode = Pin::GPIO_OUT;
 
+		return 0;
+
 	}