[CMake] How best to capture the current Date/Time

[Bill Hoffman]

Michael Jackson wrote:
> 
> On Mar 20, 2009, at 5:30 AM, Eric Noulard wrote:
> 
>> 2009/3/20 Philip Lowman <philip at yhbt.com>:
>>> On Thu, Mar 19, 2009 at 11:18 PM, Michael Jackson
>>> <mike.jackson at bluequartz.net> wrote:
>>>>
>>>> I am trying to find a nice portable solution for generating version
>>>> strings based on the date (seems reasonable). I even have my own c++ 
>>>> code
>>>> that can generate the proper string for me. The problem that I can 
>>>> not seem
>>>> to get my head around is that I need to compile and run the program 
>>>> at cmake
>>>> time which probably isn't really going to happen, at least easily.
>>>>  So. what is everyone else doing for this?
>>>>
>>>> My main goal is to automate the generation of cmake code like the
>>>> following:
>>>>
>>>> set ( ${${Project_Name}_VERSION} "2009.03.10")
>>>>
>>>> so that I can later use it for OS X bundle building.
>>>>
>>>> On Unix systems I can easily spawn a "date" command to get what I 
>>>> need but
>>>> what to do on windows?
>>
>> I use 'date' on unix and nothing but a "nodate" string on windows :-(
>>
>>>
>>> Ugly, but apparently possible with batch file scripting!
>>> http://www.tech-recipes.com/rx/956/windows-batch-file-bat-to-get-current-date-in-mmddyyyy-format/ 
>>>
>>>
>>> Another option is you could write a small program which uses 
>>> localtime() and
>>> other posix functions to get you the format that you want and then 
>>> use the
>>> output from the program via a CHECK_C_SOURCE_COMPILES configure test.
>>
>> may be the same idea, use TRY_RUN with your home made portable source
>> to get your string at CMake time.
>>
>> another solution would be to try to find some script language installed
>> (perl, python, ...) then EXECUTE_PROCESS with appropriate pieces of code
>> for getting the date you want.
>>
>> I think it would be worth a feature request for cmake -E date <format>
>> the "how to get date" is popping again and again.
>>
>> -- 
>> Erk
> 
> 
> That was the ticket. The try_run is working as best as I would expect it 
> to. I plan to wrap that code in a CMake variable so that I can trigger 
> the try_run when I need to increment the version string.
> 
> After all of this I'll probably put in a feature request for this 
> functionality to be a part of CMake. Actually, if we could just get the 
> following variables set by CMake it would be great:
> 
> CMAKE_CURRENT_YEAR
> CMAKE_CURRENT_MONTH
> CMAKE_CURRENT_DAY
> CMAKE_CURRENT_HOUR
> CMAKE_CURRENT_MINUTE
> CMAKE_CURRENT_SECOND
> 
I don't think you could do this as a set of variables.  It would be 
better as some sort of command.  file(GETDATE result) or something.

-Bill