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Re: Hard time figuring out what order-only prerequisites really do.
From: |
Angel Tsankov |
Subject: |
Re: Hard time figuring out what order-only prerequisites really do. |
Date: |
Fri, 1 Jul 2005 15:47:00 +0300 |
If this is the case, I still cannot see why it always performs the action of
this rule (excerpt from an attachment in a previous post):
IntermediateFiles/%.o: SourceFiles/%.cpp | IntermediateFiles
gcc -c $< -o $@
> Well, when you have:
>
> target: dependency
> action
>
> GNU make will perform "action" if either "target" doesn't exist or is
> older than "dependency".
>
> If you have:
>
> target: | dependency
> action
>
> GNU make will perform "action" only if "target" doesn't already exist.
>
> Angel Tsankov wrote:
>
>> I didn't get this. Could you give a more detaild explanation?
>>
>>
>>>In my view, all they do is change the meaning of "up to date" from the
>>>usual "exists and timestamp is newer" to just "exists".
>>>
>>>Noel
>>>
>>>Angel Tsankov wrote:
>>>
>>>
>>>>I'm having a really hard time what order-only prerequsites really do.
>>>>
>>>>First, I thought that they will do just fine if I want to have my object
>>>>files go in a separate folder. This makes it necessary to ensure this
>>>>folder (let's name it IntemediateFolder) exists before compilation of
>>>>each source file. Of course, this check should not render the target
>>>>(object file) out-of-date. As far as I get it all this make the
>>>>folder-existence check (and creation if necessary) appropriate for an
>>>>order-only prerequiste. However, I must be awfully wrong, 'cause I could
>>>>not come up with a makefile that does exactly this. And I've been trying
>>>>it since for a whole day...
>>>>
>>>>So, I've attached the troublesome makefile. I execute it with make 3.80
>>>>on a linux system. Could you explain to me why the script compiles the
>>>>soruce files even when the objects do exist and are newer than the
>>>>corresponding source files?
>>>>
>>>>Best wishes,
>>>>An unsuccessful rocket sceintist
>>>>_______________________________________________
>>>>Help-make mailing list
>>>>address@hidden
>>>>http://lists.gnu.org/mailman/listinfo/help-make
>>>
>>
>>
>
>
- Hard time figuring out what order-only prerequisites really do., Angel Tsankov, 2005/07/01
- Re: Hard time figuring out what order-only prerequisites really do., Noel Yap, 2005/07/01
- Re: Hard time figuring out what order-only prerequisites really do., Angel Tsankov, 2005/07/01
- Re: Hard time figuring out what order-only prerequisites really do., Noel Yap, 2005/07/01
- Re: Hard time figuring out what order-only prerequisites really do.,
Angel Tsankov <=
- Re: Hard time figuring out what order-only prerequisites really do., Noel Yap, 2005/07/01
- Re: Hard time figuring out what order-only prerequisites really do., Angel Tsankov, 2005/07/01
- Re: Hard time figuring out what order-only prerequisites really do., Noel Yap, 2005/07/01
- Re: Hard time figuring out what order-only prerequisites really do., Paul D. Smith, 2005/07/01