Re: Automatically keeping "last modified" up to date

[Allin C. <cot...@wf...>]

On Tue, 6 Aug 2013, Daniel J Sebald wrote:

> On 08/06/2013 03:01 PM, Allin Cottrell wrote:
>> On Tue, 6 Aug 2013, Ethan A Merritt wrote:
>> 
>>> On Tuesday, August 06, 2013 12:26:04 pm Allin Cottrell wrote:
>>>> There's one other fishy thing in that neighborhood. When I do
>>>> a cvs update it seems I quite often get the cvs 'M' flag
>>>> indicating that src/version.c is modified, when I certainly
>>>> haven't edited that file.
>>>> Allin Cottrell
>>> 
>>> Exactly.  That's as expected.
>>> When you run "make" it changes gnuplot_date[] in version.c file to reflect
>>> the most recently modified date.  So if you later update from CVS it sees
>>> that your local copy of version.c is different from the base copy in CVS.
>> 
>> OK, I see. And I don't think this is a big deal. But isn't it
>> sort of a principle of version control to operate a strict
>> separation between files that are supplied from the repository
>> (and hence are, in a sense, "read-only") and files that are
>> automatically generated in the course of a build? Gnuplot's
>> version.c seems to cross that line.
>
> This is sort of the assumption I made and hence the confusion.  Maybe it 
> would be better to not do the "mv" step of:
>
> sed -e '/^const char gnuplot_date/ s/"[^"]*"/"2013-08-06 "/' \
>     version.c > version.ct;
> mv version.ct version.c
>
> and just compile the derivative file.  If that were the case, then my build 
> outside the source tree would have failed because version.ct would not 
> appear.  I suppose the intent here is to allow building to proceed if the 
> user doesn't have "sed" on their system, for example.
>
> Are you building outside of the source tree?  Perhaps we are running into the 
> same issue.

I build gnuplot in its own source tree, so that's not the 
issue for me.

I just tried a CVS update and build, and this time it worked 
fine, showing the current date. Maybe something extraneous 
caused a problem before, but it seems to me there's a certain 
brittleness here.

Allin Cottrell