[hackers] [ubase] Update watch(1) to handle more accurate intervals || sin

[git]

commit 703e18185c38b869d8f001241aa6b33c832ff5dc
Author: sin <s...@2f30.org>
Date:   Sun Nov 30 14:03:25 2014 +0000

    Update watch(1) to handle more accurate intervals

diff --git a/watch.c b/watch.c
index 46411df..1508883 100644
--- a/watch.c
+++ b/watch.c
@@ -1,4 +1,5 @@
 /* See LICENSE file for copyright and license details. */
+#include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
@@ -15,14 +16,19 @@ int
 main(int argc, char *argv[])
 {
        char cmd[BUFSIZ];
-       int i, interval = 2;
+       char *end;
+       useconds_t interval = 2 * 1E6;
+       float period;
+       int i;
 
        ARGBEGIN {
        case 't':
                break;
        case 'n':
-               /* Only whole seconds for now */
-               interval = estrtol(EARGF(usage()), 10);
+               period = strtof(EARGF(usage()), &end);
+               if (*end != '\0' || errno != 0)
+                       eprintf("invalid interval\n");
+               interval = period * 1E6;
                break;
        default:
                usage();
@@ -44,7 +50,7 @@ main(int argc, char *argv[])
                printf("\x1b[2J\x1b[H"); /* clear */
                fflush(NULL);
                system(cmd);
-               sleep(interval);
+               usleep(interval);
        }
        return 0;
 }