diff --git a/Makefile b/Makefile
index 5e2a9ce..c44eebd 100644
--- a/Makefile
+++ b/Makefile
@@ -35,13 +35,13 @@ include include/Makefile
 FLAGS+=-UECOLAB_LIB -DINSTALLED_ECOLAB_LIB=\"$(PREFIX)/include\"
 
 ifdef AEGIS
-# must build and test against c++11 now, as TR1 has goone!
-CXXFLAGS+=-std=c++11
+# must build and test against c++20 now
+CXXFLAGS+=-std=c++20
 endif
 
 # when upgrading MXE, this will need to be removed 
 ifdef MXE
-CXXFLAGS+=-std=c++11
+CXXFLAGS+=-std=c++20
 endif
 
 
@@ -75,7 +75,7 @@ OBJS+=src/xdr_pack.o
 endif
 
 # build for Mac Aqua interface, requires special static build of Tk.
-ifdef MAC_OSX_TK
+ifdef AQUA
 CXXFLAGS+=-DMAC_OSX_TK 
 OBJS+=src/getContext.o
 endif
@@ -86,6 +86,8 @@ CDHDRS=
 # Clunky, but this extracts all .cd files mentioned in header files,
 CDHDRS+=$(shell bash extractCDHeaders.sh)
 
+cdhdrs: $(CDHDRS:%=include/%) graphcode.cd
+
 ifdef UNURAN
 CDHDRS+=random_unuran.cd
 endif
@@ -101,6 +103,8 @@ ELIBS=lib/libecolab$(ECOLIBS_EXT).a $(MODS:%=lib/%)
 
 # toplevel version
 include Makefile.version
+# run build CD headers before anything else
+include cdhdrs
 
 # variant of $(VERSION) that has leading 0s stripped (for sonames)
 SOVERSION=$(subst D0,D,$(subst D00,D,$(VERSION)))
@@ -116,7 +120,6 @@ endif
 
 all: all-without-models
 	$(MAKE) models 
-	-$(CHMOD) a+x models/*.tcl
 
 all-without-models: ecolab-libs lib/libecolab$(ECOLIBS_EXT).a bin/ecolab$(ECOLIBS_EXT)
 	-$(CHMOD) a+x $(SCRIPTS)
@@ -125,30 +128,6 @@ ifdef MXE
 	cp -r $(call search,lib*/tcl$(TCLVERSION)) include/tcl
 	cp -r $(call search,lib*/tk$(TCLVERSION)) include/tk
 endif
-# update Makefile.config with the configuration parameters used to build this
-	echo TK=$(TK)>$(MCFG)
-	echo ZLIB=$(ZLIB)>>$(MCFG)
-	echo READLINE=$(READLINE)>>$(MCFG)
-	echo XDR=$(XDR)>>$(MCFG)
-	echo UNURAN=$(UNURAN)>>$(MCFG)
-	echo PRNG=$(PRNG)>>$(MCFG)
-	echo GNUSL=$(GNUSL)>>$(MCFG)
-	echo PARMETIS=$(PARMETIS)>>$(MCFG)
-	echo IGRAPH=$(IGRAPH)>>$(MCFG)
-	echo SAUCY=$(SAUCY)>>$(MCFG)
-	echo CAIRO=$(CAIRO)>>$(MCFG)
-	echo PANGO=$(PANGO)>>$(MCFG)
-	echo BLT=$(BLT)>>$(MCFG)
-	echo BDB=$(BDB)>>$(MCFG)
-	echo GDBM=$(GDBM) >>$(MCFG)
-	echo GDBM_COMPAT=$(GDBM_COMPAT) >>$(MCFG)
-	echo MPI=$(MPI)>>$(MCFG)
-	echo PARALLEL=$(PARALLEL)>>$(MCFG)
-	echo OPENMP=$(OPENMP)>>$(MCFG)
-	echo GCC=$(GCC)>>$(MCFG)
-	echo NOGUI=$(NOGUI)>>$(MCFG)
-	echo AQUA=$(AQUA)>>$(MCFG)	
-	echo MAC_OSX_TK=$(MAC_OSX_TK)>>$(MCFG)
 
 ecolab-libs: lib bin 
 	$(MAKE) $(UTILS) 
@@ -156,9 +135,11 @@ ecolab-libs: lib bin
 
 .PHONY: models classdesc
 
-$(OBJS) $(MODS:%=src/%): $(CDHDRS:%=include/%) graphcode.cd
+#$(OBJS) $(MODS:%=src/%): $(CDHDRS:%=include/%) graphcode.cd
 
-$(OBJS:.o=.d) $(MODS:%.o=src/%.d):  $(ECOLAB_HOME)/$(MCFG)
+ifneq ($(MAKECMDGOALS),clean)
+$(OBJS:.o=.d) $(MODS:%.o=src/%.d): $(ECOLAB_HOME)/$(MCFG)
+endif
 
 $(CDHDRS:%=include/%): $(CLASSDESC)
 
@@ -221,6 +202,7 @@ endif
 
 .PHONY: clean
 clean: 
+	-rm $(MCFG)
 	-$(BASIC_CLEAN) generate_nauty_sizes
 	-cd src; $(BASIC_CLEAN) 
 	-cd utils; $(BASIC_CLEAN)
@@ -240,7 +222,6 @@ clean:
 	-rm -f lib/*.so lib/*.so.* bin/*
 	-rm -rf classdesc-lib cxx_repository
 	-rm -rf ii_files */ii_files
-	-rm $(MCFG)
 
 doc/ecolab/ecolab.html: doc/*.tex
 	(cd doc; ./Makedoc)
@@ -255,7 +236,7 @@ latex-docs:
 
 #bin/ecolab is a python interpreter supporting MPI
 bin/ecolab$(ECOLIBS_EXT): src/pythonMain.o lib/libecolab$(ECOLIBS_EXT).a
-	$(LINK) $(FLAGS) src/pythonMain.o -Wl,-rpath $(ECOLAB_HOME)/lib $(LIBS) $(shell pkg-config --libs python3) -o $@
+	$(LINK) $(FLAGS) src/pythonMain.o -Wl,-rpath $(ECOLAB_HOME)/lib $(LIBS) -o $@
 	-find . \( -name "*.cc" -o -name "*.h" \) -print |etags -
 
 .PHONY: install
@@ -287,10 +268,13 @@ UNURAN_LIB=$(firstword $(call search,lib*/libunuran.a))
 
 $(ECOLAB_HOME)/$(MCFG):
 	@rm -f $(MCFG)
-# absolute dependecies
-	@if [ -z "$(call search,lib*/tclConfig.sh)" ]; then \
-	   echo "Error: Cannot find TCL - please install TCL"; fi
-# optionals
+# absolute dependencies
+	@if ! $(PKG_CONFIG) --exists python3; then \
+	   echo "Error: Cannot find Python libs - please install python3-dev"; \
+	   exit 1; \
+	fi
+# optional dependecies
+	@if [ -n "$(call search,lib*/tclConfig.sh)" ]; then echo TCL=1>>$(MCFG); fi
 	@if [ -n "$(call search,lib*/tkConfig.sh)" ]; then echo TK=1>>$(MCFG); fi
 	@if [ -n "$(call search,include/zlib.h)" ]; then echo ZLIB=1>>$(MCFG); fi
 	@if [ -n "$(call search,include/readline/readline.h)" ]; then echo READLINE=1>>$(MCFG); fi
@@ -303,8 +287,7 @@ $(ECOLAB_HOME)/$(MCFG):
 	@if [ -n "$(call search,include/parmetis.h)" ]; then echo PARMETIS=1>>$(MCFG); fi
 	@if [ -n "$(call search,include/igraph/igraph.h)" ]; then echo IGRAPH=1>>$(MCFG); fi
 	@if [ -n "$(call search,include/saucy.h)" ]; then echo SAUCY=1>>$(MCFG); fi
-	@if $(PKG_CONFIG) --exists cairo; then echo CAIRO=1>>$(MCFG); \
-	elif [ -n "$(call search,include/blt.h)" ]; then echo BLT=1>>$(MCFG); fi
+	@if $(PKG_CONFIG) --exists cairo; then echo CAIRO=1>>$(MCFG); fi
 # select Berkley DB by default, 
 	@if [ -n "$(call search,include/db4/db.h)" -o -n "$(call search,include/db.h)" ]; then \
 	  echo BDB=1>>$(MCFG); \
@@ -325,6 +308,9 @@ $(ECOLAB_HOME)/$(MCFG):
 	echo GCC=$(GCC)>>$(MCFG)
 	echo NOGUI=$(NOGUI)>>$(MCFG)
 	echo AQUA=$(AQUA)>>$(MCFG)
+ifeq ($(origin XDR),"command line")
+	echo XDR=$(XDR)>>$(MCFG)
+endif
 
 #generate_nauty_sizes: generate_nauty_sizes.c
 #	$(CC) $(FLAGS) $(OPT) $< -o $@
@@ -343,12 +329,10 @@ src/getContext.o: src/getContext.cc
 #	./generate_nauty_sizes >$@
 #endif
 
-sure: all 
-	-$(MAKE) $(TESTS)
+tests:
 	-cd test; $(MAKE)
-	-cd test/test_tcl_stl; $(MAKE) 
-	-cd test/tcl-arrays; $(MAKE) 
-	-cd test/complex_tcl_args; $(MAKE) 
+
+sure: all tests
 	sh runtests test/00/*.sh
 
 # install documentation on SourceForge
diff --git a/include/Makefile b/include/Makefile
index 54d0b1c..5c60b62 100644
--- a/include/Makefile
+++ b/include/Makefile
@@ -383,7 +383,9 @@ FLAGS+=-DZLIB
 LIBS+=-lz
 endif
 
+# python
 FLAGS+=$(shell $(PKG_CONFIG) --cflags python3)
+LIBS+=$(shell $(PKG_CONFIG) --libs python3)
 
 ifdef XDR
 # libtirpc is where the XDR routines have been moved to from glibc
diff --git a/include/ecolab.h b/include/ecolab.h
index ccf3642..f341c27 100644
--- a/include/ecolab.h
+++ b/include/ecolab.h
@@ -12,6 +12,7 @@
 #ifndef ECOLAB_H
 #define ECOLAB_H
 #include <stdlib.h>
+#include "pythonBuffer.h"
 
 // mpi.h must appear before any standard library stuff
 #ifdef MPI_SUPPORT
@@ -54,6 +55,8 @@ typedef classdesc::string eco_string;
 
 namespace ecolab
 {
+  using namespace classdesc;
+  
   /* these are defined to default values, even if MPI is false */
   /// MPI process ID and number of processes
   unsigned myid();
diff --git a/models/Makefile b/models/Makefile
index 71ab8fe..5165a2a 100644
--- a/models/Makefile
+++ b/models/Makefile
@@ -37,7 +37,7 @@ endif
 $(MODELS:=.o): %.o: %.cc 
 
 # how to build a model
-$(MODELS:=.so): %.so: %.o ../lib/libecolab.a
+$(MODELS:=.so): %.so: %.o ../lib/libecolab$(ECOLIBS_EXT).a
 	$(LINK) $(FLAGS) -shared -Wl,-rpath $(ECOLAB_HOME)/lib $*.o $(LIBS) -o $@
 
 #make MacOS application bundles
diff --git a/src/ecolab.cc b/src/ecolab.cc
index 2395dc6..31911b0 100644
--- a/src/ecolab.cc
+++ b/src/ecolab.cc
@@ -11,6 +11,7 @@
 #include "cairoSurfaceImage.h"
 #include "plot.h"
 #include "pythonBuffer.h"
+#include "ecolab.h"
 #ifdef MPI_SUPPORT
 #include "graphcode.h"
 #endif
@@ -50,6 +51,18 @@ namespace ecolab
       Parallel();
     };
 
+    static PyObject* exit(Parallel* self, PyObject*)
+    {
+      if (self->target)
+        {
+#ifdef MPI_SUPPORT
+          MPIbuf b; b<<string("return")<<bcast(0);
+#endif
+          self->target=nullptr;
+        }
+      return Py_None; 
+    }
+
     PyMethodDef parallelMethods[]={
       {"exit",(PyCFunction)exit,METH_NOARGS,"Signal workers to knock off"},
       {nullptr, nullptr, 0, nullptr}
@@ -83,23 +96,11 @@ namespace ecolab
 #ifdef MPI_SUPPORT
         std::string method=PyUnicode_AsUTF8(PySequence_GetItem(args,0));
         // we need to pickle the arguments and kwargs, so leave argument support until later
-        MPIBuf b; b<<method<<bcast(0);
+        MPIbuf b; b<<method<<bcast(0);
 #endif
         return PyObject_Call(PyObject_GetAttr(target,PySequence_GetItem(args,0)),PyTuple_New(0),nullptr);
       }
 
-      static PyObject* exit(Parallel* self, PyObject*)
-      {
-        if (self->target)
-          {
-#ifdef MPI_SUPPORT
-            MPIBuf b; b<<"return"<<bcast(0);
-#endif
-            self->target=nullptr;
-          }
-        return Py_None; 
-      }
-
       static int init(PyObject* self, PyObject* args, PyObject*)
       {
         if (!PySequence_Check(args) || PySequence_Size(args)<1)
@@ -138,11 +139,11 @@ namespace ecolab
 #ifdef MPI_SUPPORT
        for (;myid()>0;)
         {
-          MPIBuf b; b.bcast(0);
+          MPIbuf b; b.bcast(0);
           std::string method; b>>method;
           if (method=="return") break;
           // we need to pickle the arguments and kwargs, so leave argument support until later
-          PyObject_Call(PyObject_GetAttrString(target,method.c_str()),Py_Tuple_new(0),nullptr);
+          PyObject_Call(PyObject_GetAttrString(target,method.c_str()),PyTuple_New(0),nullptr);
         }
 #endif
     }
diff --git a/src/pythonMain.cc b/src/pythonMain.cc
index 2e0291b..cc498e8 100644
--- a/src/pythonMain.cc
+++ b/src/pythonMain.cc
@@ -70,6 +70,9 @@ int main(int argc, char* argv[])
   for (int i=1; i<argc; ++i)
     PyList_Append(pyArgv, PyUnicode_FromString(argv[i]));
   PySys_SetObject("argv",pyArgv);
-    
-  return PyRun_SimpleFile(script,argv[1]);
+
+  int err=0;
+  if (err=PyRun_SimpleFile(script,argv[1]))
+    PyErr_Print();
+  return err;
 }
diff --git a/test/Makefile b/test/Makefile
index 27a89c1..65104db 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -23,7 +23,8 @@ GDBM+=-lgdbm
 MODELS=testParallel
 # vector-pair - doesn't currently compile - see ticket #161
 #EXTRAMODELS=test_tcl_stl.exe tcl-arrays.exe complex_tcl_args.exe
-EXES=test_omp_rw_lock testCheckpointableFile test_netcomplexity test_boostgraph test_ecostrstream posTest testarrays  callTclArgsMethod pangoTest
+#EXES=test_omp_rw_lock testCheckpointableFile test_netcomplexity test_boostgraph test_ecostrstream posTest testarrays pangoTest testParallel
+EXES=test_omp_rw_lock testCheckpointableFile test_netcomplexity test_ecostrstream posTest testarrays pangoTest 
 SPECIALS=testNDBM testBDB
 
 ifeq ($(CC),gcc)
@@ -38,7 +39,7 @@ CXXFLAGS+=-std=c++11
 endif
 
 #chmod command is to counteract AEGIS removing execute privelege from scripts
-all: $(MODELS) $(EXES) $(SPECIALS)
+all: $(MODELS:=.so) $(EXES) $(SPECIALS)
 	-$(CHMOD) a+x *.tcl
 
 ifeq ($(OS),Darwin)
@@ -50,7 +51,7 @@ $(MODELS:=.o): %.o: %.cc
 	$(CPLUSPLUS) -c -g $(FLAGS) $(CXXFLAGS) $<
 
 # how to build a model 
-$(MODELS:=.so): %.so: %.o ../lib/libecolab.a
+$(MODELS:=.so): %.so: %.o
 	$(LINK) $(FLAGS) -shared -Wl,-rpath $(ECOLAB_HOME)/lib $*.o $(LIBS) -o $@
 
 # temporary workaround until directories of same name go
diff --git a/test/testParallel.cc b/test/testParallel.cc
index 7691355..92e5c19 100644
--- a/test/testParallel.cc
+++ b/test/testParallel.cc
@@ -1,7 +1,9 @@
 #include "testParallel.h"
 #include "testParallel.cd"
+#include "ecolab.h"
+#include "ecolab_epilogue.h"
 
 Test test;
 CLASSDESC_ADD_GLOBAL(test);
-CLASSDESC_PYTHON_MODULE(test);
+CLASSDESC_PYTHON_MODULE(testParallel);
 
diff --git a/test/testParallel.h b/test/testParallel.h
index 05ce684..54efa7d 100644
--- a/test/testParallel.h
+++ b/test/testParallel.h
@@ -1,10 +1,23 @@
 #include "ecolab.h"
+#include <set>
 struct Test
 {
-  void runTest()
+  std::set<unsigned> runTest()
   {
+    std::set<unsigned> procs;
 #ifdef MPI_SUPPORT
-    MPIBuf()<<ecolab::myid()<<send(0);
+    classdesc::MPIbuf buf;
+    buf<<ecolab::myid();
+    buf.gather(0);
+    while (buf.pos()<buf.size())
+      {
+        unsigned p; buf>>p;
+        procs.insert(p);
+      }
+    assert(procs.size()==ecolab::nprocs());
+#else
+    procs.insert(0);
 #endif
+    return procs;
   }
 };
diff --git a/test/test_netcomplexity.cc b/test/test_netcomplexity.cc
index fa69911..ad867d4 100644
--- a/test/test_netcomplexity.cc
+++ b/test/test_netcomplexity.cc
@@ -29,8 +29,6 @@ bool nearly_equal(double x,double y)
   return fabs(x-y) < 1e-10*(fabs(x)+fabs(y));
 }
 
-Tcl_Interp *interp;
-
 template <class B>
 void test_iterator()
 {