I have modified the GNU textutils tail.c to allow for fractional seconds
with the -s option. e.g. "tail -f -s 1.325 filename", rather than only
whole number, as per the FIXME in the current tail.c code. The diff
follows.
Matt Rickard
--- tail.c.old 2002-07-29 04:40:21.000000000 -0400
+++ tail.c 2002-12-09 02:21:30.000000000 -0500
@@ -21,7 +21,8 @@
Original version by Paul Rubin <[EMAIL PROTECTED]>.
Extensions by David MacKenzie <[EMAIL PROTECTED]>.
- tail -f for multiple files by Ian Lance Taylor <[EMAIL PROTECTED]>. */
+ tail -f for multiple files by Ian Lance Taylor <[EMAIL PROTECTED]>.
+ Allowing fractional seconds for -s by Matt Rickard <[EMAIL PROTECTED]>. */
#include <config.h>
@@ -66,6 +67,9 @@
/* FIXME: make Follow_name the default? */
#define DEFAULT_FOLLOW_MODE Follow_descriptor
+/* Seconds to microseconds conversion factor (10^6) */
+#define SECONDS_TO_MICROSECONDS 1000000
+
enum Follow_mode
{
/* Follow the name of each file: if the file is renamed, try to reopen
@@ -177,11 +181,10 @@
/* The name this program was run with. */
char *program_name;
-/* The number of seconds to sleep between iterations.
+/* The number of microseconds 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;
+static unsigned long sleep_interval = 1000000;
/* The process ID of the process (presumably on the current host)
that is writing to all followed files. */
@@ -276,7 +279,7 @@
--pid=PID with -f, terminate after process ID, PID dies\n\
-q, --quiet, --silent never output headers giving file names\n\
-s, --sleep-interval=S with -f, each iteration lasts approximately S\n\
- (default 1) seconds\n\
+ (default 1.0) seconds\n\
-v, --verbose always output headers giving file names\n\
"), stdout);
fputs (HELP_OPTION_DESCRIPTION, stdout);
@@ -1022,7 +1025,7 @@
{
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. */
@@ -1536,15 +1539,28 @@
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)
- {
- error (EXIT_FAILURE, 0,
- _("%s: invalid number of seconds"), optarg);
- }
- sleep_interval = tmp_ulong;
+ double tmp_double, other_tmp_double;
+ char *endp;
+ tmp_double = strtod(optarg, &endp);
+ if(endp > optarg) /* valid double */
+ {
+ other_tmp_double = tmp_double * SECONDS_TO_MICROSECONDS;
+ if(other_tmp_double <= (double)ULONG_MAX) /* valid
+ unsigned long) */
+ {
+ sleep_interval = other_tmp_double;
+ }
+ else
+ {
+ error (EXIT_FAILURE, 0,
+ _("%s: invalid number of seconds"), optarg);
+ }
+ }
+ else
+ {
+ error (EXIT_FAILURE, 0,
+ _("%s: invalid number of seconds"), optarg);
+ }
}
break;
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