Update perlfunc/require to describe NXDOMAIN caching... er, you

know what I mean.

p4raw-id: //depot/perl@21417

1 files changed, 28 insertions, 20 deletions

diff --git a/pod/perlfunc.pod b/pod/perlfunc.pod
index f2e2b97e5d..4d4efc53df 100644
--- a/pod/perlfunc.pod
+++ b/pod/perlfunc.pod
@@ -4054,28 +4054,36 @@ version should be used instead.
 
 Otherwise, demands that a library file be included if it hasn't already
 been included.  The file is included via the do-FILE mechanism, which is
-essentially just a variety of C<eval>.  Has semantics similar to the following
-subroutine:
+essentially just a variety of C<eval>.  Has semantics similar to the
+following subroutine:
 
     sub require {
-	my($filename) = @_;
-	return 1 if $INC{$filename};
-	my($realfilename,$result);
-	ITER: {
-	    foreach $prefix (@INC) {
-		$realfilename = "$prefix/$filename";
-		if (-f $realfilename) {
-		    $INC{$filename} = $realfilename;
-		    $result = do $realfilename;
-		    last ITER;
-		}
-	    }
-	    die "Can't find $filename in \@INC";
-	}
-	delete $INC{$filename} if $@ || !$result;
-	die $@ if $@;
-	die "$filename did not return true value" unless $result;
-	return $result;
+       my ($filename) = @_;
+       if (exists $INC{$filename}) {
+           return 1 if $INC{$filename};
+           die "Compilation failed in require";
+       }
+       my ($realfilename,$result);
+       ITER: {
+           foreach $prefix (@INC) {
+               $realfilename = "$prefix/$filename";
+               if (-f $realfilename) {
+                   $INC{$filename} = $realfilename;
+                   $result = do $realfilename;
+                   last ITER;
+               }
+           }
+           die "Can't find $filename in \@INC";
+       }
+       if ($@) {
+           $INC{$filename} = undef;
+           die $@;
+       } elsif (!$result) {
+           delete $INC{$filename};
+           die "$filename did not return true value";
+       } else {
+           return $result;
+       }
     }
 
 Note that the file will not be included twice under the same specified