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digitalmars.D - __TIMESTAMP_UNIXEPOCH__ instead of useless __TIMESTAMP__?

reply Timothee Cour <thelastmammoth gmail.com> writes:
__TIMESTAMP__ is pretty useless:
`string literal of the date and time of compilation "www mmm dd hh:mm:ss yyyy"`
eg:Wed Jan 24 11:03:56 2018
which is a weird non-standard format not understood by std.datetime.
__DATE__ and __TIME__ are also pretty useless.

Could we have __TIMESTAMP_UNIXEPOCH__ (or perhaps
__TIMESTAMP_SYSTIME__ to get a SysTime) ?

from that, users can convert to whatever format they want.
Jan 24 2018
next sibling parent reply rikki cattermole <rikki cattermole.co.nz> writes:
On 24/01/2018 7:18 PM, Timothee Cour wrote:

 __TIMESTAMP__ is pretty useless:
 `string literal of the date and time of compilation "www mmm dd hh:mm:ss yyyy"`
 eg:Wed Jan 24 11:03:56 2018
 which is a weird non-standard format not understood by std.datetime.
 __DATE__ and __TIME__ are also pretty useless.
 
 Could we have __TIMESTAMP_UNIXEPOCH__ (or perhaps
 __TIMESTAMP_SYSTIME__ to get a SysTime) ?


That can be a library solution from __TIMESTAMP__.
Jan 24 2018
next sibling parent Timothee Cour <thelastmammoth gmail.com> writes:
On Wed, Jan 24, 2018 at 5:50 PM, rikki cattermole via Digitalmars-d
<digitalmars-d puremagic.com> wrote:

 On 24/01/2018 7:18 PM, Timothee Cour wrote:

 __TIMESTAMP__ is pretty useless:
 `string literal of the date and time of compilation "www mmm dd hh:mm:ss
 yyyy"`
 eg:Wed Jan 24 11:03:56 2018
 which is a weird non-standard format not understood by std.datetime.
 __DATE__ and __TIME__ are also pretty useless.

 Could we have __TIMESTAMP_UNIXEPOCH__ (or perhaps
 __TIMESTAMP_SYSTIME__ to get a SysTime) ?



 That can be a library solution from __TIMESTAMP__.


no, there's missing time zone information, so we can't reconstruct
unix epoch nor utc time
Jan 24 2018
prev sibling parent Jonathan M Davis <newsgroup.d jmdavisprog.com> writes:
On Wednesday, January 24, 2018 18:25:21 Timothee Cour via Digitalmars-d 
wrote:

 On Wed, Jan 24, 2018 at 5:50 PM, rikki cattermole via Digitalmars-d

 <digitalmars-d puremagic.com> wrote:

 On 24/01/2018 7:18 PM, Timothee Cour wrote:

 __TIMESTAMP__ is pretty useless:
 `string literal of the date and time of compilation "www mmm dd
 hh:mm:ss
 yyyy"`
 eg:Wed Jan 24 11:03:56 2018
 which is a weird non-standard format not understood by std.datetime.
 __DATE__ and __TIME__ are also pretty useless.

 Could we have __TIMESTAMP_UNIXEPOCH__ (or perhaps
 __TIMESTAMP_SYSTIME__ to get a SysTime) ?


 That can be a library solution from __TIMESTAMP__.


 no, there's missing time zone information, so we can't reconstruct
 unix epoch nor utc time


Yeah, and since getting that information requires calling C functions that
can't be called during CTFE, you can't interpret the value at compile time -
which is the only time that you're guaranteed that the system running the
code has the same timezone as when __TIMESTAMP__ was intepreted. Either
__TIMESTAMP__ would need to be changed (which I doubt Walter would allow for
fear of something relying on the format), or we'd need something like
__TIMESTAMP_UNIXTIME__ or whatever.

The only viable alternative that I can think of at the moment is to pass the
information to the program as part of the build. But all in all, I think
that __TIMESTAMP__ is pretty useless as-is unless you just want a ballpark
date and time for when the build was generated and don't care what format
it's in.

In most cases, I'd argue that it's better not to have anything like
__TIMESTAMP__, because then the build is guaranteed to not be reproducible,
but presumably you found some use for it, since you're looking for a version
of __TIMESTAMP__ that's in a more standard format.

- Jonathan M Davis
Jan 24 2018
prev sibling parent reply Walter Bright <newshound2 digitalmars.com> writes:
On 1/24/2018 11:18 AM, Timothee Cour wrote:

 __TIMESTAMP__ is pretty useless:
 `string literal of the date and time of compilation "www mmm dd hh:mm:ss yyyy"`
 eg:Wed Jan 24 11:03:56 2018
 which is a weird non-standard format not understood by std.datetime.


It's the format emitted by the Standard C library function asctime():

     http://pubs.opengroup.org/onlinepubs/009695399/functions/asctime.html


 __DATE__ and __TIME__ are also pretty useless.


These also match the format of the Standard C preprocessor macros __DATE__ and 
__TIME__.
Jan 25 2018
parent reply Steven Schveighoffer <schveiguy yahoo.com> writes:
On 1/25/18 4:39 AM, Walter Bright wrote:

 On 1/24/2018 11:18 AM, Timothee Cour wrote:

 __TIMESTAMP__ is pretty useless:
 `string literal of the date and time of compilation "www mmm dd 
 hh:mm:ss yyyy"`
 eg:Wed Jan 24 11:03:56 2018
 which is a weird non-standard format not understood by std.datetime.


 
 It's the format emitted by the Standard C library function asctime():
 
      http://pubs.opengroup.org/onlinepubs/009695399/functions/asctime.html
 

 __DATE__ and __TIME__ are also pretty useless.


 
 These also match the format of the Standard C preprocessor macros 
 __DATE__ and __TIME__.


We should support __ISOTIMESTAMP__ which is readable by std.datetime [1].

The compiler is in D after all, we can use it! Or at least, port enough 
of std.datetime to display it :)

-Steve

[1] 
https://dlang.org/phobos/std_datetime_systime.html#.SysTime.toISOExtString
Jan 25 2018
parent reply Kagamin <spam here.lot> writes:
Just a numeric (long) result from `time` - more compact storage 
and simpler implementation.
Jan 27 2018
parent Steven Schveighoffer <schveiguy yahoo.com> writes:
On 1/27/18 4:05 AM, Kagamin wrote:

 Just a numeric (long) result from `time` - more compact storage and 
 simpler implementation.


A numeric value is fine, but I would be cautious about relying on 
time(). It's not guaranteed to return 64 bits, meaning the y2k35 bug 
would affect D ;)

However, having a nice actual timestamp string may be more useful. My 
suggestion also contains the timezone, so it has more info (and this was 
a further request by the OP).

-Steve
Jan 27 2018