--- a/examples/tcp/wscript	Tue Feb 14 17:57:15 2012 +0000
+++ b/examples/tcp/wscript	Tue Feb 14 18:44:16 2012 +0000
@@ -2,7 +2,7 @@
 
 def build(bld):
     obj = bld.create_ns3_program('tcp-large-transfer',
-                                 ['point-to-point', 'applications', 'internet'])
+                                 ['visualizer', 'point-to-point', 'applications', 'internet'])
     obj.source = 'tcp-large-transfer.cc'
 
     obj = bld.create_ns3_program('tcp-nsc-lfn',

--- a/src/visualizer/wscript	Tue Feb 14 17:57:15 2012 +0000
+++ b/src/visualizer/wscript	Tue Feb 14 18:44:16 2012 +0000
@@ -1,24 +1,53 @@
 ## -*- Mode: python; py-indent-offset: 4; indent-tabs-mode: nil; coding: utf-8; -*-
 import Options
 
+required_python_modules = [
+    'gtk',
+    'goocanvas',
+    'pygraphviz',
+    ]
+
 def configure(conf):
     # If Python was explicitly disabled, then add this module to the
     # list of modules that won't be built if they are enabled.
-    if Options.options.python_disable:
+    conf.env['ENABLE_PYVIZ'] = True
+    if not conf.check_optional_feature("python"):
+        conf.env['ENABLE_PYVIZ'] = False
+        conf.report_optional_feature("PyViz", "PyViz visualizer",
+                                     False,
+                                     "Python Bindings are needed but not enabled")
         conf.env['MODULES_NOT_BUILT'].append('visualizer')
+        return
+
+    modules_missing = []
+    for pymod in required_python_modules:
+        try:
+            conf.check_python_module(pymod)
+        except conf.errors.ConfigurationError:
+            modules_missing.append(pymod)
+    if modules_missing:
+        conf.report_optional_feature("PyViz", "PyViz visualizer",
+                                     False, "Missing python modules: %s" % (', '.join(modules_missing),))
+        conf.env['ENABLE_PYVIZ'] = False
+        conf.env['MODULES_NOT_BUILT'].append('visualizer')
+        return
+
+    conf.report_optional_feature("PyViz", "PyViz visualizer", True, None)
+
 
 def build(bld):
-    # Don't do anything for this module if Python was explicitly
+
+    module = bld.create_ns3_module('visualizer', ['internet', 'wifi', 'point-to-point'])
+    headers = bld.new_task_gen(features=['ns3header'])
+    headers.module = 'visualizer'
+
+    # Don't do anything more for this module if Python was explicitly
     # disabled.
-    if 'visualizer' in bld.env['MODULES_NOT_BUILT']:
+    if not bld.env['ENABLE_PYVIZ']:
         return
 
-    headers = bld.new_task_gen(features=['ns3header'])
-    headers.module = 'visualizer'
-    headers.source = [
-        ]
 
-    module = bld.create_ns3_module('visualizer', ['internet', 'wifi', 'point-to-point'])
+    headers.source = []
 
     # XXX This file was added so that static builds would work on
     # Darwin, which doesn't like modules with no source files.  It
@@ -32,9 +61,6 @@
         'model/dummy-file-for-static-builds.cc',
         ]
 
-    if not bld.env['ENABLE_PYTHON_BINDINGS']:
-        return
-
     module.features.append('pyembed')
     #module.env.append_value('CXXFLAGS', module.env['shlib_CXXFLAGS'])
     #module.includes = '.'

--- a/wscript	Tue Feb 14 17:57:15 2012 +0000
+++ b/wscript	Tue Feb 14 18:44:16 2012 +0000
@@ -270,6 +270,11 @@
 def report_optional_feature(conf, name, caption, was_enabled, reason_not_enabled):
     conf.env.append_value('NS3_OPTIONAL_FEATURES', [(name, caption, was_enabled, reason_not_enabled)])
 
+def check_optional_feature(conf, name):
+    for (name1, caption, was_enabled, reason_not_enabled) in conf.env.NS3_OPTIONAL_FEATURES:
+        if name1 == name:
+            return was_enabled
+    raise KeyError("Feature %r not declared yet" % (name,))
 
 # starting with waf 1.6, conf.check() becomes fatal by default if the
 # test fails, this alternative method makes the test non-fatal, as it
@@ -287,6 +292,7 @@
     conf.check_nonfatal = types.MethodType(_check_nonfatal, conf)
     conf.check_compilation_flag = types.MethodType(_check_compilation_flag, conf)
     conf.report_optional_feature = types.MethodType(report_optional_feature, conf)
+    conf.check_optional_feature = types.MethodType(check_optional_feature, conf)
     conf.env['NS3_OPTIONAL_FEATURES'] = []
 
     conf.check_tool('compiler_c')
@@ -364,6 +370,8 @@
 
     conf.env['MODULES_NOT_BUILT'] = []
 
+    conf.sub_config('bindings/python')
+
     conf.sub_config('src')
 
     # Set the list of enabled modules.
@@ -396,8 +404,6 @@
             if not conf.env['NS3_ENABLED_MODULES']:
                 raise WafError('Exiting because the ' + not_built + ' module can not be built and it was the only one enabled.')
 
-    conf.sub_config('bindings/python')
-
     conf.sub_config('src/mpi')
 
     # for suid bits