Limit @ISA to actual DBM in AnyDBM

diff --git a/lib/AnyDBM_File.pm b/lib/AnyDBM_File.pm
index e6a1503..aff3c7c 100644 (file)
--- a/lib/AnyDBM_File.pm
+++ b/lib/AnyDBM_File.pm
@@ -1,11 +1,14 @@
 package AnyDBM_File;
-use vars qw(@ISA);
 
+use vars qw(@ISA);
 @ISA = qw(NDBM_File DB_File GDBM_File SDBM_File ODBM_File) unless @ISA;
 
 my $mod;
 for $mod (@ISA) {
-    return 1 if eval "require $mod"
+    if (eval "require $mod") {
+       @ISA = ($mod);  # if we leave @ISA alone, warnings abound
+       return 1;
+    }
 }
 
 die "No DBM package was successfully found or installed";
@@ -15,7 +18,7 @@ die "No DBM package was successfully found or installed";
 
 AnyDBM_File - provide framework for multiple DBMs
 
-NDBM_File, ODBM_File, SDBM_File, GDBM_File - various DBM implementations
+NDBM_File, DB_File, GDBM_File, SDBM_File, ODBM_File - various DBM implementations
 
 =head1 SYNOPSIS
 
@@ -30,14 +33,8 @@ L<DB_File>), GDBM, SDBM (which is always there--it comes with Perl), and
 finally ODBM.   This way old programs that used to use NDBM via dbmopen()
 can still do so, but new ones can reorder @ISA:
 
-    @AnyDBM_File::ISA = qw(DB_File GDBM_File NDBM_File);
-
-Note, however, that an explicit use overrides the specified order:
-
-    use GDBM_File;
-    @AnyDBM_File::ISA = qw(DB_File GDBM_File NDBM_File);
-
-will only find GDBM_File.
+    BEGIN { @AnyDBM_File::ISA = qw(DB_File GDBM_File NDBM_File) }
+    use AnyDBM_File;
 
 Having multiple DBM implementations makes it trivial to copy database formats: