* ext/dbm/dbm.c (fdbm_initialize): accept optional 3rd argument to

specify an open flag.
  (Init_dbm): define open flags: DBM::READER, DBM::WRITER, DBM::WRCREAT
  and DBM::NEWDB.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@6326 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/dbm/test_dbm.rb

@@ -11,7 +11,7 @@ if defined? DBM
   require 'fileutils'
 
   class TestDBM < Test::Unit::TestCase
-    TMPROOT = "#{Dir.tmpdir}/ruby-gdbm.#{$$}"
+    TMPROOT = "#{Dir.tmpdir}/ruby-dbm.#{$$}"
 
     def setup
       Dir.mkdir TMPROOT
@@ -21,8 +21,31 @@ if defined? DBM
       FileUtils.rm_rf TMPROOT if File.directory?(TMPROOT)
     end
 
+    def test_reader_open
+      DBM.open("#{TMPROOT}/a") {}
+      v = DBM.open("#{TMPROOT}/a", nil, DBM::READER) {|d|
+        # Errno::EPERM is raised on Solaris which use ndbm.
+        # DBMError is raised on Debian which use gdbm. 
+        assert_raises(Errno::EPERM, DBMError) { d["k"] = "v" }
+        true
+      }
+      assert(v)
+    end
+
+    def test_newdb_open
+      DBM.open("#{TMPROOT}/a") {|dbm|
+        dbm["k"] = "v"
+      }
+      v = DBM.open("#{TMPROOT}/a", nil, DBM::NEWDB) {|d|
+        assert_equal(0, d.length)
+        assert_nil(d["k"])
+        true
+      }
+      assert(v)
+    end
+
     def test_freeze
-      DBM.open("#{TMPROOT}/a.dbm") {|d|
+      DBM.open("#{TMPROOT}/a") {|d|
         d.freeze
         assert_raises(TypeError) { d["k"] = "v" }
       }