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

[Mark Galeck (CW)]

Thank you everybody for the advanced discussion from which I learnt a lot.

To answer Eli's question about the usage situation, I had a target which was a 
.tar file, and it's prerequisites were symbolic links put in one directory and 
pointing to various places.  

Even though the filesystem supports sub-second timestamps, the tar utility 
making the target did not and half of the time rounds the time backwards to the 
nearest second.  However, the ln -s command sets up the modify timestamp of the 
link to sub-second resolution.  And I was using MAKEFLAGS := -LrR so that the 
timestamps of the links themselves mattered.  

So I would build, .tar file gets created, and then I build again without any 
other changes, sometimes gets created again based on the backwards rounding.  


As for .LOW_RESOLUTION_TIME, it is a recent feature, I am actually using emake, 
mostly compatible with make, but not necessarily yet available or installed by 
IT on my server with the latest revision compatibility of GNU Make.  Can't use 
.LOW_RESOLUTION_TIME yet.


My current solution is to just put sleep 1 when I need it - this problem only 
happens in recipes which do not have to be executed fast.