strict-w-proof the ?DBM_File, from Paul Marquess.

p4raw-id: //depot/perl@8848

8 files changed, 121 insertions, 81 deletions

diff --git a/ext/GDBM_File/GDBM_File.pm b/ext/GDBM_File/GDBM_File.pm
index fe87dd0856..074b976386 100644
--- a/ext/GDBM_File/GDBM_File.pm
+++ b/ext/GDBM_File/GDBM_File.pm
@@ -40,6 +40,7 @@ L<perl(1)>, L<DB_File(3)>, L<perldbmfilter>.
 package GDBM_File;
 
 use strict;
+use warnings;
 our($VERSION, @ISA, @EXPORT, $AUTOLOAD);
 
 require Carp;
diff --git a/ext/NDBM_File/NDBM_File.pm b/ext/NDBM_File/NDBM_File.pm
index 99aae17d5c..b2804597a1 100644
--- a/ext/NDBM_File/NDBM_File.pm
+++ b/ext/NDBM_File/NDBM_File.pm
@@ -1,10 +1,7 @@
 package NDBM_File;
 
-BEGIN {
-    if ($] >= 5.002) {
-	use strict;
-    }
-}
+use strict;
+use warnings;
 
 require Tie::Hash;
 use XSLoader ();
diff --git a/ext/ODBM_File/ODBM_File.pm b/ext/ODBM_File/ODBM_File.pm
index 4244eb966f..9e8e008e02 100644
--- a/ext/ODBM_File/ODBM_File.pm
+++ b/ext/ODBM_File/ODBM_File.pm
@@ -1,6 +1,7 @@
 package ODBM_File;
 
 use strict;
+use warnings;
 
 require Tie::Hash;
 use XSLoader ();
diff --git a/ext/SDBM_File/SDBM_File.pm b/ext/SDBM_File/SDBM_File.pm
index 4d1411bf34..ee82a54145 100644
--- a/ext/SDBM_File/SDBM_File.pm
+++ b/ext/SDBM_File/SDBM_File.pm
@@ -1,6 +1,7 @@
 package SDBM_File;
 
 use strict;
+use warnings;
 
 require Tie::Hash;
 use XSLoader ();
diff --git a/t/lib/gdbm.t b/t/lib/gdbm.t
index af83fdda81..ecbd662f26 100755
--- a/t/lib/gdbm.t
+++ b/t/lib/gdbm.t
@@ -11,6 +11,10 @@ BEGIN {
     }
 }
 
+use strict;
+use warnings;
+
+
 use GDBM_File;
 
 print "1..68\n";
@@ -18,9 +22,10 @@ print "1..68\n";
 unlink <Op.dbmx*>;
 
 umask(0);
-print (tie(%h,GDBM_File,'Op.dbmx', &GDBM_WRCREAT, 0640) ? "ok 1\n" : "not ok 1\n");
+my %h ;
+print (tie(%h,'GDBM_File','Op.dbmx', &GDBM_WRCREAT, 0640) ? "ok 1\n" : "not ok 1\n");
 
-$Dfile = "Op.dbmx.pag";
+my $Dfile = "Op.dbmx.pag";
 if (! -e $Dfile) {
 	($Dfile) = <Op.dbmx*>;
 }
@@ -28,11 +33,12 @@ if ($^O eq 'amigaos' || $^O eq 'os2' || $^O eq 'MSWin32' || $^O eq 'dos') {
     print "ok 2 # Skipped: different file permission semantics\n";
 }
 else {
-    ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,
+    my ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,
      $blksize,$blocks) = stat($Dfile);
     print (($mode & 0777) == 0640 ? "ok 2\n" : "not ok 2\n");
 }
-while (($key,$value) = each(%h)) {
+my $i = 0;
+while (my ($key,$value) = each(%h)) {
     $i++;
 }
 print (!$i ? "ok 3\n" : "not ok 3\n");
@@ -57,7 +63,7 @@ $h{'goner2'} = 'snork';
 delete $h{'goner2'};
 
 untie(%h);
-print (tie(%h,GDBM_File,'Op.dbmx', &GDBM_WRCREAT, 0640) ? "ok 4\n" : "not ok 4\n");
+print (tie(%h,'GDBM_File','Op.dbmx', &GDBM_WRCREAT, 0640) ? "ok 4\n" : "not ok 4\n");
 
 $h{'j'} = 'J';
 $h{'k'} = 'K';
@@ -82,12 +88,12 @@ $h{'goner3'} = 'snork';
 delete $h{'goner1'};
 delete $h{'goner3'};
 
-@keys = keys(%h);
-@values = values(%h);
+my @keys = keys(%h);
+my @values = values(%h);
 
 if ($#keys == 29 && $#values == 29) {print "ok 5\n";} else {print "not ok 5\n";}
 
-while (($key,$value) = each(%h)) {
+while (my ($key,$value) = each(%h)) {
     if ($key eq $keys[$i] && $value eq $values[$i] && $key eq lc($value)) {
 	$key =~ y/a-z/A-Z/;
 	$i++ if $key eq $value;
@@ -103,17 +109,17 @@ $h{'foo'} = '';
 $h{''} = 'bar';
 
 # check cache overflow and numeric keys and contents
-$ok = 1;
+my $ok = 1;
 for ($i = 1; $i < 200; $i++) { $h{$i + 0} = $i + 0; }
 for ($i = 1; $i < 200; $i++) { $ok = 0 unless $h{$i} == $i; }
 print ($ok ? "ok 8\n" : "not ok 8\n");
 
-($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,
+my ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,
    $blksize,$blocks) = stat($Dfile);
 print ($size > 0 ? "ok 9\n" : "not ok 9\n");
 
 @h{0..200} = 200..400;
-@foo = @h{0..200};
+my @foo = @h{0..200};
 print join(':',200..400) eq join(':',@foo) ? "ok 10\n" : "not ok 10\n";
 
 print ($h{'foo'} eq '' ? "ok 11\n" : "not ok 11\n");
@@ -137,6 +143,7 @@ sub ok
    package Another ;
 
    use strict ;
+   use warnings ;
 
    open(FILE, ">SubDB.pm") or die "Cannot open SubDB.pm: $!\n" ;
    print FILE <<'EOM' ;
@@ -211,6 +218,7 @@ EOM
 {
    # DBM Filter tests
    use strict ;
+   use warnings ;
    my (%h, $db) ;
    my ($fetch_key, $store_key, $fetch_value, $store_value) = ("") x 4 ;
 
@@ -317,6 +325,7 @@ EOM
     # DBM Filter with a closure
 
     use strict ;
+    use warnings ;
     my (%h, $db) ;
 
     unlink <Op.dbmx*>;
@@ -361,7 +370,7 @@ EOM
     ok(54, $result{"store key"} eq "store key - 2: [fred jim]");
     ok(55, $result{"store value"} eq "store value - 2: [joe john]");
     ok(56, $result{"fetch key"} eq "fetch key - 1: [fred]");
-    ok(57, $result{"fetch value"} eq "");
+    ok(57, ! defined $result{"fetch value"} );
     ok(58, $_ eq "original") ;
 
     ok(59, $h{"fred"} eq "joe");
@@ -379,6 +388,7 @@ EOM
 {
    # DBM Filter recursion detection
    use strict ;
+   use warnings ;
    my (%h, $db) ;
    unlink <Op.dbmx*>;
 
diff --git a/t/lib/ndbm.t b/t/lib/ndbm.t
index a8344444c8..e56fcd938a 100755
--- a/t/lib/ndbm.t
+++ b/t/lib/ndbm.t
@@ -12,6 +12,18 @@ BEGIN {
     }
 }
 
+use strict;
+use warnings;
+
+sub ok
+{
+    my $no = shift ;
+    my $result = shift ;
+
+    print "not " unless $result ;
+    print "ok $no\n" ;
+}
+
 require NDBM_File;
 #If Fcntl is not available, try 0x202 or 0x102 for O_RDWR|O_CREAT
 use Fcntl;
@@ -21,9 +33,10 @@ print "1..65\n";
 unlink <Op.dbmx*>;
 
 umask(0);
-print (tie(%h,NDBM_File,'Op.dbmx', O_RDWR|O_CREAT, 0640) ? "ok 1\n" : "not ok 1\n");
+my %h;
+ok(1, tie(%h,'NDBM_File','Op.dbmx', O_RDWR|O_CREAT, 0640));
 
-$Dfile = "Op.dbmx.pag";
+my $Dfile = "Op.dbmx.pag";
 if (! -e $Dfile) {
 	($Dfile) = <Op.dbmx*>;
 }
@@ -31,11 +44,12 @@ if ($^O eq 'amigaos' || $^O eq 'os2' || $^O eq 'MSWin32') {
     print "ok 2 # Skipped: different file permission semantics\n";
 }
 else {
-    ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,
+    my ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,
      $blksize,$blocks) = stat($Dfile);
     print (($mode & 0777) == 0640 ? "ok 2\n" : "not ok 2\n");
 }
-while (($key,$value) = each(%h)) {
+my $i = 0;
+while (my ($key,$value) = each(%h)) {
     $i++;
 }
 print (!$i ? "ok 3\n" : "not ok 3\n");
@@ -60,7 +74,7 @@ $h{'goner2'} = 'snork';
 delete $h{'goner2'};
 
 untie(%h);
-print (tie(%h,NDBM_File,'Op.dbmx', &O_RDWR, 0640) ? "ok 4\n" : "not ok 4\n");
+print (tie(%h,'NDBM_File','Op.dbmx', &O_RDWR, 0640) ? "ok 4\n" : "not ok 4\n");
 
 $h{'j'} = 'J';
 $h{'k'} = 'K';
@@ -85,12 +99,12 @@ $h{'goner3'} = 'snork';
 delete $h{'goner1'};
 delete $h{'goner3'};
 
-@keys = keys(%h);
-@values = values(%h);
+my @keys = keys(%h);
+my @values = values(%h);
 
 if ($#keys == 29 && $#values == 29) {print "ok 5\n";} else {print "not ok 5\n";}
 
-while (($key,$value) = each(%h)) {
+while (my ($key,$value) = each(%h)) {
     if ($key eq $keys[$i] && $value eq $values[$i] && $key eq lc($value)) {
 	$key =~ y/a-z/A-Z/;
 	$i++ if $key eq $value;
@@ -106,17 +120,17 @@ $h{'foo'} = '';
 $h{''} = 'bar';
 
 # check cache overflow and numeric keys and contents
-$ok = 1;
+my $ok = 1;
 for ($i = 1; $i < 200; $i++) { $h{$i + 0} = $i + 0; }
 for ($i = 1; $i < 200; $i++) { $ok = 0 unless $h{$i} == $i; }
 print ($ok ? "ok 8\n" : "not ok 8\n");
 
-($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,
+my ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,
    $blksize,$blocks) = stat($Dfile);
 print ($size > 0 ? "ok 9\n" : "not ok 9\n");
 
 @h{0..200} = 200..400;
-@foo = @h{0..200};
+my @foo = @h{0..200};
 print join(':',200..400) eq join(':',@foo) ? "ok 10\n" : "not ok 10\n";
 
 print ($h{'foo'} eq '' ? "ok 11\n" : "not ok 11\n");
@@ -125,21 +139,13 @@ print ($h{''} eq 'bar' ? "ok 12\n" : "not ok 12\n");
 untie %h;
 unlink 'Op.dbmx.dir', $Dfile;
 
-sub ok
-{
-    my $no = shift ;
-    my $result = shift ;
-
-    print "not " unless $result ;
-    print "ok $no\n" ;
-}
-
 {
    # sub-class test
 
    package Another ;
 
    use strict ;
+   use warnings ;
 
    open(FILE, ">SubDB.pm") or die "Cannot open SubDB.pm: $!\n" ;
    print FILE <<'EOM' ;
@@ -147,6 +153,7 @@ sub ok
    package SubDB ;
 
    use strict ;
+   use warnings ;
    use vars qw(@ISA @EXPORT) ;
 
    require Exporter ;
@@ -209,6 +216,7 @@ EOM
 {
    # DBM Filter tests
    use strict ;
+   use warnings ;
    my (%h, $db) ;
    my ($fetch_key, $store_key, $fetch_value, $store_value) = ("") x 4 ;
 
@@ -315,6 +323,7 @@ EOM
     # DBM Filter with a closure
 
     use strict ;
+    use warnings ;
     my (%h, $db) ;
 
     unlink <Op.dbmx*>;
@@ -359,7 +368,7 @@ EOM
     ok(52, $result{"store key"} eq "store key - 2: [fred jim]");
     ok(53, $result{"store value"} eq "store value - 2: [joe john]");
     ok(54, $result{"fetch key"} eq "fetch key - 1: [fred]");
-    ok(55, $result{"fetch value"} eq "");
+    ok(55, ! defined $result{"fetch value"} );
     ok(56, $_ eq "original") ;
 
     ok(57, $h{"fred"} eq "joe");
@@ -377,6 +386,7 @@ EOM
 {
    # DBM Filter recursion detection
    use strict ;
+   use warnings ;
    my (%h, $db) ;
    unlink <Op.dbmx*>;
 
diff --git a/t/lib/odbm.t b/t/lib/odbm.t
index f2c1bb6d32..b935d049e5 100755
--- a/t/lib/odbm.t
+++ b/t/lib/odbm.t
@@ -12,6 +12,18 @@ BEGIN {
     }
 }
 
+use strict;
+use warnings;
+
+sub ok
+{
+    my $no = shift ;
+    my $result = shift ;
+
+    print "not " unless $result ;
+    print "ok $no\n" ;
+}
+
 require ODBM_File;
 #If Fcntl is not available, try 0x202 or 0x102 for O_RDWR|O_CREAT
 use Fcntl;
@@ -21,9 +33,10 @@ print "1..66\n";
 unlink <Op.dbmx*>;
 
 umask(0);
-print (tie(%h,ODBM_File,'Op.dbmx', O_RDWR|O_CREAT, 0640) ? "ok 1\n" : "not ok 1\n");
+my %h;
+ok(1, tie(%h,'ODBM_File','Op.dbmx', O_RDWR|O_CREAT, 0640));
 
-$Dfile = "Op.dbmx.pag";
+my $Dfile = "Op.dbmx.pag";
 if (! -e $Dfile) {
 	($Dfile) = <Op.dbmx*>;
 }
@@ -31,11 +44,12 @@ if ($^O eq 'amigaos' || $^O eq 'os2' || $^O eq 'MSWin32') {
     print "ok 2 # Skipped: different file permission semantics\n";
 }
 else {
-    ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,
+    my ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,
      $blksize,$blocks) = stat($Dfile);
     print (($mode & 0777) == 0640 ? "ok 2\n" : "not ok 2\n");
 }
-while (($key,$value) = each(%h)) {
+my $i = 0;
+while (my ($key,$value) = each(%h)) {
     $i++;
 }
 print (!$i ? "ok 3\n" : "not ok 3\n");
@@ -60,7 +74,7 @@ $h{'goner2'} = 'snork';
 delete $h{'goner2'};
 
 untie(%h);
-print (tie(%h,ODBM_File,'Op.dbmx', O_RDWR, 0640) ? "ok 4\n" : "not ok 4\n");
+print (tie(%h,'ODBM_File','Op.dbmx', O_RDWR, 0640) ? "ok 4\n" : "not ok 4\n");
 
 $h{'j'} = 'J';
 $h{'k'} = 'K';
@@ -85,12 +99,12 @@ $h{'goner3'} = 'snork';
 delete $h{'goner1'};
 delete $h{'goner3'};
 
-@keys = keys(%h);
-@values = values(%h);
+my @keys = keys(%h);
+my @values = values(%h);
 
 if ($#keys == 29 && $#values == 29) {print "ok 5\n";} else {print "not ok 5\n";}
 
-while (($key,$value) = each(%h)) {
+while (my ($key,$value) = each(%h)) {
     if ($key eq $keys[$i] && $value eq $values[$i] && $key eq lc($value)) {
 	$key =~ y/a-z/A-Z/;
 	$i++ if $key eq $value;
@@ -106,17 +120,17 @@ $h{'foo'} = '';
 $h{''} = 'bar';
 
 # check cache overflow and numeric keys and contents
-$ok = 1;
+my $ok = 1;
 for ($i = 1; $i < 200; $i++) { $h{$i + 0} = $i + 0; }
 for ($i = 1; $i < 200; $i++) { $ok = 0 unless $h{$i} == $i; }
 print ($ok ? "ok 8\n" : "not ok 8\n");
 
-($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,
+my ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,
    $blksize,$blocks) = stat($Dfile);
 print ($size > 0 ? "ok 9\n" : "not ok 9\n");
 
 @h{0..200} = 200..400;
-@foo = @h{0..200};
+my @foo = @h{0..200};
 print join(':',200..400) eq join(':',@foo) ? "ok 10\n" : "not ok 10\n";
 
 print ($h{'foo'} eq '' ? "ok 11\n" : "not ok 11\n");
@@ -125,21 +139,13 @@ print ($h{''} eq 'bar' ? "ok 12\n" : "not ok 12\n");
 untie %h;
 unlink 'Op.dbmx.dir', $Dfile;
 
-sub ok
-{
-    my $no = shift ;
-    my $result = shift ;
-
-    print "not " unless $result ;
-    print "ok $no\n" ;
-}
-
 {
    # sub-class test
 
    package Another ;
 
    use strict ;
+   use warnings ;
 
    open(FILE, ">SubDB.pm") or die "Cannot open SubDB.pm: $!\n" ;
    print FILE <<'EOM' ;
@@ -147,6 +153,7 @@ sub ok
    package SubDB ;
 
    use strict ;
+   use warnings ;
    use vars qw(@ISA @EXPORT) ;
 
    require Exporter ;
@@ -209,6 +216,7 @@ EOM
 {
    # DBM Filter tests
    use strict ;
+   use warnings ;
    my (%h, $db) ;
    my ($fetch_key, $store_key, $fetch_value, $store_value) = ("") x 4 ;
 
@@ -317,6 +325,7 @@ EOM
     # DBM Filter with a closure
 
     use strict ;
+    use warnings ;
     my (%h, $db) ;
 
     unlink <Op.dbmx*>;
@@ -361,7 +370,7 @@ EOM
     ok(52, $result{"store key"} eq "store key - 2: [fred jim]");
     ok(53, $result{"store value"} eq "store value - 2: [joe john]");
     ok(54, $result{"fetch key"} eq "fetch key - 1: [fred]");
-    ok(55, $result{"fetch value"} eq "");
+    ok(55, ! defined $result{"fetch value"} );
     ok(56, $_ eq "original") ;
 
     ok(57, $h{"fred"} eq "joe");
@@ -379,6 +388,7 @@ EOM
 {
    # DBM Filter recursion detection
    use strict ;
+   use warnings ;
    my (%h, $db) ;
    unlink <Op.dbmx*>;
 
diff --git a/t/lib/sdbm.t b/t/lib/sdbm.t
index d60447e960..3221ca46ed 100755
--- a/t/lib/sdbm.t
+++ b/t/lib/sdbm.t
@@ -11,6 +11,19 @@ BEGIN {
 	exit 0;
     }
 }
+
+use strict;
+use warnings;
+
+sub ok
+{
+    my $no = shift ;
+    my $result = shift ;
+
+    print "not " unless $result ;
+    print "ok $no\n" ;
+}
+
 require SDBM_File;
 #If Fcntl is not available, try 0x202 or 0x102 for O_RDWR|O_CREAT
 use Fcntl;
@@ -20,10 +33,10 @@ print "1..68\n";
 unlink <Op_dbmx.*>;
 
 umask(0);
-print (tie(%h,SDBM_File,'Op_dbmx', O_RDWR|O_CREAT, 0640)
-       ? "ok 1\n" : "not ok 1\n");
+my %h ;
+ok(1, tie %h,'SDBM_File','Op_dbmx', O_RDWR|O_CREAT, 0640);
 
-$Dfile = "Op_dbmx.pag";
+my $Dfile = "Op_dbmx.pag";
 if (! -e $Dfile) {
 	($Dfile) = <Op_dbmx.*>;
 }
@@ -31,11 +44,12 @@ if ($^O eq 'amigaos' || $^O eq 'os2' || $^O eq 'MSWin32' || $^O eq 'dos') {
     print "ok 2 # Skipped: different file permission semantics\n";
 }
 else {
-    ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,
+    my ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,
      $blksize,$blocks) = stat($Dfile);
     print (($mode & 0777) == 0640 ? "ok 2\n" : "not ok 2\n");
 }
-while (($key,$value) = each(%h)) {
+my $i = 0;
+while (my ($key,$value) = each(%h)) {
     $i++;
 }
 print (!$i ? "ok 3\n" : "not ok 3\n");
@@ -60,7 +74,7 @@ $h{'goner2'} = 'snork';
 delete $h{'goner2'};
 
 untie(%h);
-print (tie(%h,SDBM_File,'Op_dbmx', O_RDWR, 0640) ? "ok 4\n" : "not ok 4\n");
+print (tie(%h,'SDBM_File','Op_dbmx', O_RDWR, 0640) ? "ok 4\n" : "not ok 4\n");
 
 $h{'j'} = 'J';
 $h{'k'} = 'K';
@@ -85,12 +99,12 @@ $h{'goner3'} = 'snork';
 delete $h{'goner1'};
 delete $h{'goner3'};
 
-@keys = keys(%h);
-@values = values(%h);
+my @keys = keys(%h);
+my @values = values(%h);
 
 if ($#keys == 29 && $#values == 29) {print "ok 5\n";} else {print "not ok 5\n";}
 
-while (($key,$value) = each(%h)) {
+while (my ($key,$value) = each(%h)) {
     if ($key eq $keys[$i] && $value eq $values[$i] && $key eq lc($value)) {
 	$key =~ y/a-z/A-Z/;
 	$i++ if $key eq $value;
@@ -106,38 +120,30 @@ $h{'foo'} = '';
 $h{''} = 'bar';
 
 # check cache overflow and numeric keys and contents
-$ok = 1;
+my $ok = 1;
 for ($i = 1; $i < 200; $i++) { $h{$i + 0} = $i + 0; }
 for ($i = 1; $i < 200; $i++) { $ok = 0 unless $h{$i} == $i; }
 print ($ok ? "ok 8\n" : "not ok 8\n");
 
-($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,
+my ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,
    $blksize,$blocks) = stat($Dfile);
 print ($size > 0 ? "ok 9\n" : "not ok 9\n");
 
 @h{0..200} = 200..400;
-@foo = @h{0..200};
+my @foo = @h{0..200};
 print join(':',200..400) eq join(':',@foo) ? "ok 10\n" : "not ok 10\n";
 
 print ($h{'foo'} eq '' ? "ok 11\n" : "not ok 11\n");
 print ($h{''} eq 'bar' ? "ok 12\n" : "not ok 12\n");
 
 
-sub ok
-{
-    my $no = shift ;
-    my $result = shift ;
-
-    print "not " unless $result ;
-    print "ok $no\n" ;
-}
-
 {
    # sub-class test
 
    package Another ;
 
    use strict ;
+   use warnings ;
 
    open(FILE, ">SubDB.pm") or die "Cannot open SubDB.pm: $!\n" ;
    print FILE <<'EOM' ;
@@ -145,6 +151,7 @@ sub ok
    package SubDB ;
 
    use strict ;
+   use warnings ;
    use vars qw( @ISA @EXPORT) ;
 
    require Exporter ;
@@ -213,6 +220,7 @@ unlink <Op_dbmx*>, $Dfile;
 {
    # DBM Filter tests
    use strict ;
+   use warnings ;
    my (%h, $db) ;
    my ($fetch_key, $store_key, $fetch_value, $store_value) = ("") x 4 ;
 
@@ -319,6 +327,7 @@ unlink <Op_dbmx*>, $Dfile;
     # DBM Filter with a closure
 
     use strict ;
+     use warnings ;
     my (%h, $db) ;
 
     unlink <Op_dbmx*>;
@@ -363,7 +372,7 @@ unlink <Op_dbmx*>, $Dfile;
     ok(54, $result{"store key"} eq "store key - 2: [fred jim]");
     ok(55, $result{"store value"} eq "store value - 2: [joe john]");
     ok(56, $result{"fetch key"} eq "fetch key - 1: [fred]");
-    ok(57, $result{"fetch value"} eq "");
+    ok(57, ! defined $result{"fetch value"} );
     ok(58, $_ eq "original") ;
 
     ok(59, $h{"fred"} eq "joe");
@@ -381,6 +390,7 @@ unlink <Op_dbmx*>, $Dfile;
 {
    # DBM Filter recursion detection
    use strict ;
+   use warnings ;
    my (%h, $db) ;
    unlink <Op_dbmx*>;