Re: Automake's file locking (was Re: Autoconf/Automake is not using version from AC_INIT)

[Bob Friesenhahn]

On Thu, 28 Jan 2021, Zack Weinberg wrote:
> The main reason I can think of, not to do this, is that it would make
> the locking strategy incompatible with that used by older autom4te;
> this could come up, for instance, if you’ve got your source directory
> on NFS and you’re building on two different clients in two different
> build directories.  On the other hand, this kind of version skew is
> going to cause problems anyway when they fight over who gets to write
> generated scripts to the source directory, so maybe it would be ok to
> declare “don’t do that” and move on.  What do others think?

This is exactly what I do.  I keep the source files on a file server 
so that I can build on several different types of clients.  This used 
to even include Microsoft Windows clients using CIFS.

The lock appears to be taken speculatively since it is taken before 
Autotools checks that there is something to do.  It would be nicer if 
Autotools could check first if there is something to do, acquire the 
lock, check if there is still something to do, and then do the work.

The most common case is that there is nothing for Autotools to do 
since the user is most often doing a 'make' for some other purpose.

Bob
--
Bob Friesenhahn
bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
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