Re: Fix remake rule-induced test failures with HP-UX make.

[Ralf Wildenhues]

[ adding autoconf-patches ]

* Ralf Wildenhues wrote on Sat, Jan 15, 2011 at 11:31:55AM CET:
> Quoting parts of:
> http://autobuild.josefsson.org/automake/log-201101150749395803000.txt

> I'm not quite sure why HP-UX make seems to trigger rebuild rules for
> prerequisites that have the exact time stamps as targets (in this case,
> config.status and subdir Makefile, but I also tried with a reduced
> makefile), but it is not Posix conforming.  Working around it properly
> would probably require sleeping inside config.status (an obvious no-go),
> and in practice it should not do more harm than updating some rules more
> than necessary.

Found it documented in HP-UX/IA 11.31 make(1):

      If no target names are specified on the command line, make updates the
      first target in the (first) makefile that is not an inference rule.  A
      target is updated in two cases: firstly, if it depends on files that
      are newer than the target; secondly, if it depends on files that have
      same modification time as that of the target.  Missing files are
      deemed to be out-of-date.  [...]

Anybody have a support contract to report this Posix violation upstream?

OK to commit?

Thanks,
Ralf

    docs: HP-UX make remakes targets with same time stamps as prereqs
    
    * doc/autoconf.texi (Timestamps and Make): Document HP-UX 11.31
    make issue with targets having the same time stamps as their
    prerequisites.
    
    Signed-off-by: Ralf Wildenhues <address@hidden>

diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index 9f5494e..81664e4 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -20183,7 +20183,9 @@ Timestamps and Make
         date >dest-stamp
 @end example
 
-
+Apart from timestamp resolution, there are also differences in handling
+equal timestamps.  HP-UX @command{make} updates targets if it has the
+same time stamp as one of its prerequisites, in violation of Posix rules.
 
 
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