Implemented `-h' option.

Allow non-root users to get syntax information.
Use correct computation of standard deviation.

diff --git a/src/oping.c b/src/oping.c
index 5f0940d..37f64b2 100644 (file)
--- a/src/oping.c
+++ b/src/oping.c
@@ -115,7 +115,7 @@ int read_options (int argc, char **argv)
 
        while (1)
        {
-               optchar = getopt (argc, argv, "46c:i:");
+               optchar = getopt (argc, argv, "46c:hi:");
 
                if (optchar == -1)
                        break;
@@ -145,6 +145,7 @@ int read_options (int argc, char **argv)
                                }
                                break;
 
+                       case 'h':
                        default:
                                usage_exit (argv[0]);
                }
@@ -256,17 +257,17 @@ int main (int argc, char **argv)
        int optind;
        int i;
 
+       optind = read_options (argc, argv);
+
+       if (optind >= argc)
+               usage_exit (argv[0]);
+
        if (geteuid () != 0)
        {
                fprintf (stderr, "Need superuser privileges to open a RAW socket. Sorry.\n");
                return (1);
        }
 
-       optind = read_options (argc, argv);
-
-       if (optind >= argc)
-               usage_exit (argv[0]);
-
        if ((ping = ping_construct ()) == NULL)
        {
                fprintf (stderr, "ping_construct failed\n");
@@ -400,7 +401,7 @@ int main (int argc, char **argv)
                        num_total = (double) context->req_rcvd;
 
                        average = context->latency_total / num_total;
-                       deviation = sqrt ((context->latency_total_square / num_total) - (average * average));
+                       deviation = sqrt (context->latency_total_square - (num_total * average * average));
 
                        printf ("rtt min/avg/max/sdev = %.3f/%.3f/%.3f/%.3f ms\n",
                                        context->latency_min,