On 14 Jan 2023 21:27, Jacob Bachmeyer wrote: > Mike Frysinger wrote: > > --- a/lib/Automake/FileUtils.pm > > +++ b/lib/Automake/FileUtils.pm > > @@ -42,6 +42,11 @@ use Exporter; > > use File::stat; > > use IO::File; > > > > +# Perl's builtin stat does not provide sub-second resolution. Use > > Time::HiRes > > +# if it's available instead. Hopefully one day perl will update. > > +# https://github.com/Perl/perl5/issues/17900 > > +my $have_time_hires = eval { require Time::HiRes; }; > > + > > use Automake::Channels; > > use Automake::ChannelDefs; > > > > @@ -115,10 +120,18 @@ sub mtime ($) > > return 0 > > if $file eq '-' || ! -f $file; > > > > - my $stat = stat ($file) > > - or fatal "cannot stat $file: $!"; > > - > > - return $stat->mtime; > > + if ($have_time_hires) > > + { > > + my @stat = Time::HiRes::stat ($file) > > + or fatal "cannot stat $file: $!"; > > + return $stat[9]; > > + } > > + else > > + { > > + my $stat = stat ($file) > > + or fatal "cannot stat $file: $!"; > > + return $stat->mtime; > > + } > > } > > If you change that variable to a constant, you can eliminate the runtime > overhead entirely, since Perl optimizes if(1) and if(0) and folds > constants at compile time. > > Something like: > > use constant HAVE_Time_HiRes => eval { require Time::HiRes; }; > > Then: > > if (HAVE_Time_HiRes) > ... > > If you do this, Perl will inline the block actually used and elide the > branch at runtime. This is generally useful for any test that can only > go one way in a specific run of the program.
thanks, i'll integrate that idea. i'm by no means a perl programmer. -mike
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