From b24bb543e97bc7ad440e66c5a1aa3cd0e62e5a69 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Sun, 27 Sep 2009 19:27:00 +0200
Subject: Print proper usage, complain if no names provided

---
 examples/hello/driver.cxx | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/examples/hello/driver.cxx b/examples/hello/driver.cxx
index c211601..6641d4b 100644
--- a/examples/hello/driver.cxx
+++ b/examples/hello/driver.cxx
@@ -9,6 +9,15 @@
 
 using namespace std;
 
+void
+usage ()
+{
+  cerr << "usage: driver <options> <names>" << endl
+       << "  [--help]" << endl
+       << "  [--greeting|-g <string>]" << endl
+       << "  [--exclamations|-e <integer>]" << endl;
+}
+
 int
 main (int argc, char* argv[])
 {
@@ -19,10 +28,17 @@ main (int argc, char* argv[])
 
     if (o.help ())
     {
-      cerr << "hello v. 1.0.0" << endl;
+      usage ();
       return 0;
     }
 
+    if (end == argc)
+    {
+      cerr << "no names provided" << endl;
+      usage ();
+      return 1;
+    }
+
     for (int i = end; i < argc; i++)
     {
       cout << o.greeting () << ", " << argv[i];
@@ -36,6 +52,7 @@ main (int argc, char* argv[])
   catch (const cli::exception& e)
   {
     cerr << e << endl;
+    usage ();
     return 1;
   }
 }
-- 
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