From 43812f1ad57b4f2d9dbb3dd6e5dc6ea3229b5032 Mon Sep 17 00:00:00 2001
From: Alvaro Lopes <alvieboy@alvie.com>
Date: Fri, 30 Oct 2009 17:07:30 +0000
Subject: [PATCH] Add help and check for serial port

---
 UI/display.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/UI/display.c b/UI/display.c
index 6710aa5..53b8cb2 100644
--- a/UI/display.c
+++ b/UI/display.c
@@ -121,12 +121,25 @@ gboolean vref_changed(GtkWidget *widget)
 	return TRUE;
 }
 
+int help(char*cmd)
+{
+	printf("Usage: %s serialport\n\n",cmd);
+	printf("  example: %s /dev/ttyUSB0\n\n",cmd);
+	return -1;
+}
+
 int main(int argc,char **argv)
 {
 	GtkWidget*scale_zoom;
 	gtk_init(&argc,&argv);
 	unsigned char data[512];
-	serial_init(argv[1]);
+
+	if (argc<2)
+		return help(argv[0]);
+
+	if (serial_init(argv[1])<0)
+		return -1;
+
 	window = gtk_window_new(GTK_WINDOW_TOPLEVEL);