hwclock --show format

sys-utils/hwclock.c display_time(const bool hclock_valid, struct timeval hwctime) · line 698

Quoted 12 lines · J William Piggott

sys-utils/hwclock.c +9 -3

-             lt = localtime(&hwctime.tv_sec);
-             strftime(ctime_now, sizeof(ctime_now), format, lt);
-             printf(_("%s and %06d microseconds\n"), ctime_now, (int)hwctime.tv_usec);
+             struct tm lt;
+             int zhour, zmin;
+
+             lt = *localtime(&hwctime.tv_sec);
+             zhour = - timezone / 60 / 60;
+             zmin = abs(timezone / 60 % 60);
+             printf(_("%4d-%.2d-%.2d %02d:%02d:%02d.%06d%+02d:%02d\n"),
+                    lt.tm_year + 1900, lt.tm_mon + 1, lt.tm_mday, lt.tm_hour,
+                    lt.tm_min, lt.tm_sec, (int)hwctime.tv_usec, zhour, zmin);

Some notes:

* what's wrong with strftime?

* We already use ISO time in util-linux and we use time designator 'T' (separator between date and time).

* tv_usec is "long"

* fraction separator is decimal mark, either a comma or a dot, but with a preference for a comma according to ISO 8601:2004 (wikipedia).

-- we already use comma in util-linux, exception is logger where I see dot :-(

Anyway, it would be really nice to have a function for this purpose in lib/timeutils.c to avoid duplication and creativity :-) Something like:

    strtime_iso_8601(char buf, size_t bufsz, struct tm tm, struct timeval frac, int flags);

where flags are

    enum {
         ISO_8601_TIMEZONE   = (1 << 1)
         ISO_8601_USEC       = (1 << 2)
         ...
    };

then we can use this function in lslogins, dmesg, hwclock, last, logger, ... etc. I can also imagine:

strtime_short_ctime()
strtime_ctime() (ctime without \n)

Comments?

sys-utils/hwclock.c display_time(const bool hclock_valid, struct timeval hwctime) · line 698

Quoted 12 lines · J William Piggott

sys-utils/hwclock.c +0 -3

-		lt = localtime(&hwctime.tv_sec);
-		strftime(ctime_now, sizeof(ctime_now), format, lt);
-		printf(_("%s and %06d microseconds\n"), ctime_now,

(int)hwctime.tv_usec); + struct tm lt;

sys-utils/hwclock.c +8 -0

+		int zhour, zmin;
+
+		lt = *localtime(&hwctime.tv_sec);
+		zhour = - timezone / 60 / 60;
+		zmin = abs(timezone / 60 % 60);
+		printf(_("%4d-%.2d-%.2d %02d:%02d:%02d.%06d%+02d:%02d\n"),
+		       lt.tm_year + 1900, lt.tm_mon + 1, lt.tm_mday, lt.tm_hour,
+		       lt.tm_min, lt.tm_sec, (int)hwctime.tv_usec, zhour, zmin);

Some notes:

* what's wrong with strftime?

* We already use ISO time in util-linux and we use time designator 'T' (separator between date and time).

* tv_usec is "long"

* fraction separator is decimal mark, either a comma or a dot, but with a preference for a comma according to ISO 8601:2004 (wikipedia).

-- we already use comma in util-linux, exception is logger where I see dot :-(

Anyway, it would be really nice to have a function for this purpose in lib/timeutils.c to avoid duplication and creativity :-) Something like:

strtime_iso_8601(char buf, size_t bufsz, struct tm tm, struct
timeval frac, int flags);

where flags are

    enum {
         ISO_8601_TIMEZONE   = (1 << 1)
         ISO_8601_USEC       = (1 << 2)
         ...
    };

then we can use this function in lslogins, dmesg, hwclock, last, logger, ... etc. I can also imagine:

strtime_short_ctime()
strtime_ctime() (ctime without \n)

Comments?

Karel

sys-utils/hwclock.c display_time(const bool hclock_valid, struct timeval hwctime) · line 698

Quoted 12 lines · J William Piggott

sys-utils/hwclock.c +9 -3

-		lt = localtime(&hwctime.tv_sec);
-		strftime(ctime_now, sizeof(ctime_now), format, lt);
-		printf(_("%s and %06d microseconds\n"), ctime_now, (int)hwctime.tv_usec);
+		struct tm lt;
+		int zhour, zmin;
+
+		lt = *localtime(&hwctime.tv_sec);
+		zhour = - timezone / 60 / 60;
+		zmin = abs(timezone / 60 % 60);
+		printf(_("%4d-%.2d-%.2d %02d:%02d:%02d.%06d%+02d:%02d\n"),
+		       lt.tm_year + 1900, lt.tm_mon + 1, lt.tm_mday, lt.tm_hour,
+		       lt.tm_min, lt.tm_sec, (int)hwctime.tv_usec, zhour, zmin);

Some notes:

* what's wrong with strftime?

* We already use ISO time in util-linux and we use time designator 'T' (separator between date and time).

* tv_usec is "long"

* fraction separator is decimal mark, either a comma or a dot, but with a preference for a comma according to ISO 8601:2004 (wikipedia).

-- we already use comma in util-linux, exception is logger where I see dot :-(

Anyway, it would be really nice to have a function for this purpose in lib/timeutils.c to avoid duplication and creativity :-) Something like:

    strtime_iso_8601(char buf, size_t bufsz, struct tm tm, struct timeval frac, int flags);

where flags are

    enum {
         ISO_8601_TIMEZONE   = (1 << 1)
         ISO_8601_USEC       = (1 << 2)
         ...
    };

then we can use this function in lslogins, dmesg, hwclock, last, logger, ... etc. I can also imagine:

strtime_short_ctime()
strtime_ctime() (ctime without \n)

Comments?

Karel

Quoted 17 lines · Karel Zak

Quoted 11 lines · J William Piggott

sys-utils/hwclock.c +0 -3

-		lt = localtime(&hwctime.tv_sec);
-		strftime(ctime_now, sizeof(ctime_now), format, lt);
-		printf(_("%s and %06d microseconds\n"), ctime_now,

(int)hwctime.tv_usec); + struct tm lt;

sys-utils/hwclock.c +7 -0

+		int zhour, zmin;
+
+		lt = *localtime(&hwctime.tv_sec);
+		zhour = - timezone / 60 / 60;
+		zmin = abs(timezone / 60 % 60);
+		printf(_("%4d-%.2d-%.2d %02d:%02d:%02d.%06d%+02d:%02d\n"),
+		       lt.tm_year + 1900, lt.tm_mon + 1, lt.tm_mday,

Quoted 2 lines

lt.tm_hour, + lt.tm_min, lt.tm_sec, (int)hwctime.tv_usec,
zhour, zmin);

Some notes:

Quoted 1 line

* what's wrong with strftime?

Why use resources on strftime when 8601 prints directly?

While it can do other formatting, I see strftime's main purpose as converting tm numbers into strings like: January, Monday, etc.

Quoted 2 lines

* We already use ISO time in util-linux and we use time designator 'T' (separator between date and time).

I chose to use the optional space as a compromise between machine friendly and human friendly, this is commonly done I think.

Quoted 1 line

* tv_usec is "long"

Fixed: I followed the example from the recent commit c211401 (for code consistency, which is why I originally used the int cast), and cast it to long; although I do not understand why as it is already long. All that needed to be done was to change the conversion length modifier and drop the cast.

PULL:

[email protected]:jwpi/util-linux.git 020716

for you to fetch changes up to

Quoted 6 lines

* fraction separator is decimal mark, either a comma or a dot, but with a preference for a comma according to ISO 8601:2004 (wikipedia).

-- we already use comma in util-linux, exception is logger where
I see dot :-(

I actually modeled the format after:

date --rfc-3339=ns

2016-02-16 20:13:25.601508440-05:00

3339 is a subset of 8601 that requires using a period for the radix point. As I said previously, I chose this as a compromise between machine and human readability. As it is output to tty by default, I thought doing so might mitigate any push back against the format change.

I am not strongly opposed to using 'T' as the date-time delimiter or comma as the radix point. I just think 'space' and 'period' are a commonly used compromise.

Quoted 16 lines

Anyway, it would be really nice to have a function for this purpose in lib/timeutils.c to avoid duplication and creativity :-) Something like:

strtime_iso_8601(char buf, size_t bufsz, struct tm tm, struct
timeval frac, int flags);

where flags are

    enum {
         ISO_8601_TIMEZONE   = (1 << 1)
         ISO_8601_USEC       = (1 << 2)
         ...
    };

Quoted 7 lines

then we can use this function in lslogins, dmesg, hwclock, last, logger, ... etc. I can also imagine:

strtime_short_ctime()
strtime_ctime() (ctime without \n)

Comments?

Also, perhaps all the above only using something similar to coreutil's fprintftime, so it prints directly using less resources.

Quoted 1 line

Karel

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Quoted 16 lines · Karel Zak

sys-utils/hwclock.c display_time(const bool hclock_valid, struct timeval hwctime) · line 698

Quoted 12 lines · J William Piggott

sys-utils/hwclock.c +9 -3

-		lt = localtime(&hwctime.tv_sec);
-		strftime(ctime_now, sizeof(ctime_now), format, lt);
-		printf(_("%s and %06d microseconds\n"), ctime_now, (int)hwctime.tv_usec);
+		struct tm lt;
+		int zhour, zmin;
+
+		lt = *localtime(&hwctime.tv_sec);
+		zhour = - timezone / 60 / 60;
+		zmin = abs(timezone / 60 % 60);
+		printf(_("%4d-%.2d-%.2d %02d:%02d:%02d.%06d%+02d:%02d\n"),
+		       lt.tm_year + 1900, lt.tm_mon + 1, lt.tm_mday, lt.tm_hour,
+		       lt.tm_min, lt.tm_sec, (int)hwctime.tv_usec, zhour, zmin);

Some notes:

Quoted 1 line

* what's wrong with strftime?

Why use resources on strftime when 8601 prints directly?

While it can do other formatting, I see strftime's main purpose as converting tm numbers into strings like: January, Monday, etc.

Quoted 17 lines

Anyway, it would be really nice to have a function for this purpose in lib/timeutils.c to avoid duplication and creativity :-) Something like:

    strtime_iso_8601(char buf, size_t bufsz, struct tm tm, struct timeval frac, int flags);

where flags are

    enum {
         ISO_8601_TIMEZONE   = (1 << 1)
         ISO_8601_USEC       = (1 << 2)
         ...
    };

then we can use this function in lslogins, dmesg, hwclock, last, logger, ... etc. I can also imagine:

Quoted 4 lines

strtime_short_ctime()
strtime_ctime() (ctime without \n)

Comments?

Also, perhaps all the above only using something similar to coreutil's fprintftime, so it prints directly using less resources.

Quoted 20 lines · J William Piggott

Quoted 17 lines · Karel Zak

sys-utils/hwclock.c display_time(const bool hclock_valid, struct timeval hwctime) · line 698

Quoted 12 lines · J William Piggott

sys-utils/hwclock.c +9 -3

-		lt = localtime(&hwctime.tv_sec);
-		strftime(ctime_now, sizeof(ctime_now), format, lt);
-		printf(_("%s and %06d microseconds\n"), ctime_now, (int)hwctime.tv_usec);
+		struct tm lt;
+		int zhour, zmin;
+
+		lt = *localtime(&hwctime.tv_sec);
+		zhour = - timezone / 60 / 60;
+		zmin = abs(timezone / 60 % 60);
+		printf(_("%4d-%.2d-%.2d %02d:%02d:%02d.%06d%+02d:%02d\n"),
+		       lt.tm_year + 1900, lt.tm_mon + 1, lt.tm_mday, lt.tm_hour,
+		       lt.tm_min, lt.tm_sec, (int)hwctime.tv_usec, zhour, zmin);

Some notes:

* what's wrong with strftime?

Quoted 4 lines

Why use resources on strftime when 8601 prints directly?

While it can do other formatting, I see strftime's main purpose as converting tm numbers into strings like: January, Monday, etc.

It does more things for you, see lt.tm_year + 1900, lt.tm_mon + 1, calculation of the time zone hours, timezone minutes...