patch for tail: fractional-second --sleep-interval when doing "tail -f"

[Erik Rossen]

This patch elimates a FIXME: adding fractional-second sleep intervals
for the "tail -f" command.

The following diff is against the tail.c in the textutils package of
Debian woody, but it is probably not too different from the GNU
original.

-- 
Erik Rossen                         ^    OpenPGP key: 2935D0B9
[EMAIL PROTECTED]                 /e\   "Use GnuPG, see the
http://www.multimania.com/rossen   ---    black helicopters."

--- tail.c      Thu Apr 11 21:05:28 2002
+++ tail.c.NEW  Thu Apr 11 21:06:39 2002
@@ -170,8 +170,8 @@
 /* The number of seconds to sleep between iterations.
    During one iteration, every file name or descriptor is checked to
    see if it has changed.  */
-/* FIXME: allow fractional seconds */
-static unsigned int sleep_interval = 1;
+/* sleep interval defaults to 1,000,000 microseconds */
+static unsigned long sleep_interval = 1000000;
 
 /* The process ID of the process (presumably on the current host)
    that is writing to all followed files.  */
@@ -921,7 +921,7 @@
        {
          if (writer_is_dead)
            break;
-         sleep (sleep_interval);
+         usleep (sleep_interval);
 
          /* Once the writer is dead, read the files once more to
             avoid a race condition.  */
@@ -1408,14 +1408,14 @@
        case 's':
          {
            strtol_error s_err;
-           unsigned long int tmp_ulong;
-           s_err = xstrtoul (optarg, NULL, 10, &tmp_ulong, "");
-           if (s_err != LONGINT_OK || tmp_ulong > UINT_MAX)
+           double tmp_d;
+           s_err = xstrtod (optarg, NULL, &tmp_d);
+           if (s_err != LONGINT_OK || (unsigned long) (tmp_d*1000000.0) > UINT_MAX)
              {
                error (EXIT_FAILURE, 0,
                       _("%s: invalid number of seconds"), optarg);
              }
-           sleep_interval = tmp_ulong;
+           sleep_interval = (unsigned long) (tmp_d*1000000.0);
          }
          break;
 

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