1 files changed, 4 insertions, 0 deletions
diff --git a/it.class b/it.class
index 0a3fc18..f9c5846 100644
--- a/it.class
+++ b/it.class
@@ -839,7 +839,11 @@ static function getopt($usage, $p = array())
 		if ($longoptname || $shortoptname)
 		{
 			if ($longoptname && ($shortoptname || $shortoptname === "0"))
+			{
+				if ($alias[$shortoptname])
+					it::error("getopt: short option -$shortoptname is used twice: --{$alias[$shortoptname]} and --$longoptname!");
 				$alias[$shortoptname] = $longoptname;
+			}
 
 			$witharg[$longoptname ? $longoptname : $shortoptname] = $longoptarg || $shortoptarg;
 		}