Re: updating target at the end of recipe, after updating prerequisites, might not work?

[Paul Smith]

On Mon, 2011-11-14 at 11:29 -0500, David Boyce wrote:
> On Mon, Nov 14, 2011 at 9:25 AM, Paul Smith <address@hidden> wrote:
> > Also, writing 0 bytes to a file does not (at least in my
> > experiment) change its modtime.
> 
> I believe it depends on O_TRUNC. The command ">foo" always updates foo
> but ">>foo" does not.

Sure but that also truncates the file.  It could very well be that you
don't want the file you're touching to lose all its content :-).

For typical make sentinel files, which are often only created so they
exist and have 0 length anyway that's fine.  But touch is a generic
utility.

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