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

[Michael Jackson]

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

that would be _really_ helpful.

Thanks to everyone for the suggestions.
----
Mike Jackson