diff --git a/setup.py b/setup.py
index e0586ef..7bea403 100644
--- a/setup.py
+++ b/setup.py
@@ -250,7 +261,7 @@ class PyBuildExt(build_ext):

         build_ext.build_extensions(self)

-        longest = max([len(e.name) for e in self.extensions])
+        longest = max([len(e.name) for e in self.extensions] + [0])
         if self.failed:
             longest = max(longest, max([len(name) for name in self.failed]))