diff --git a/llvm_cbuilder/builder.py b/llvm_cbuilder/builder.py
index 3fce585..88516df 100644
--- a/llvm_cbuilder/builder.py
+++ b/llvm_cbuilder/builder.py
@@ -434,7 +434,8 @@ class CDefinition(CBuilder):
     @classmethod
     def define(cls, module, **kws):
         functype = lc.Type.function(cls._retty_, [v for k, v in cls._argtys_])
-        func = module.get_or_insert_function(functype, name=cls._name_)
+        name = cls._name_ % kws
+        func = module.get_or_insert_function(functype, name=name)
         if not func.is_declaration: # already defined?
             raise NameError(func)
 
diff --git a/parallel_vectorize.py b/parallel_vectorize.py
index 42aea26..2d9421f 100644
--- a/parallel_vectorize.py
+++ b/parallel_vectorize.py
@@ -95,7 +95,7 @@ class ParallelUFunc(CDefinition):
 
     which should be implemented in subclass or mixin.
     '''
-    _name_   = 'parallel_ufunc'
+    _name_   = 'parallel_ufunc_%(ThreadCount)d'
     _argtys_ = [
         ('func',       C.void_p),
         ('worker',     C.void_p),
@@ -317,7 +317,9 @@ class UFuncCore(CDefinition):
         '''
         raise NotImplementedError
 
-class _SpecializedParallelUFunc(ParallelUFunc, ParallelUFuncPosixMixin):
+
+class SpecializedParallelUFunc(CDefinition):
+    _name_ = 'specialized_parallel_ufunc_%(ThreadCount)d_%(FuncName)s'
     _argtys_ = [
         ('args',       C.pointer(C.char_p)),
         ('dimensions', C.pointer(C.intp)),
@@ -325,8 +327,14 @@ class _SpecializedParallelUFunc(ParallelUFunc, ParallelUFuncPosixMixin):
         ('data',       C.void_p),
     ]
 
-    def body(self, args, dimensions, steps, data, ThreadCount=1):
-        pass
+    def body(self, args, dimensions, steps, data,
+             PUFuncDef, CoreDef, Func, FuncName, ThreadCount=1):
+        pufunc = self.depends(PUFuncDef, ThreadCount=ThreadCount)
+        core = self.depends(CoreDef)
+        func = self.depends(Func)
+        to_void_p = lambda x: x.cast(C.void_p)
+        pufunc(to_void_p(func), to_void_p(core), args, dimensions, steps, data)
+        self.ret()
 
 class PThreadAPI(CExternal):
     pthread_t = C.void_p
diff --git a/test_parallel_vectorize.py b/test_parallel_vectorize.py
index 4fde372..e16d206 100644
--- a/test_parallel_vectorize.py
+++ b/test_parallel_vectorize.py
@@ -47,10 +47,17 @@ class Tester(CDefinition):
         ArgCount = 2
         WorkCount = 10000
 
-        parallel_ufunc = self.depends(ParallelUFuncPosix,
-                                      ThreadCount=ThreadCount)
-        ufunc_core = self.depends(UFuncCore_D_D)
-        worker = self.depends(Work_D_D)
+#        parallel_ufunc = self.depends(ParallelUFuncPosix,
+#                                      ThreadCount=ThreadCount)
+#        ufunc_core = self.depends(UFuncCore_D_D)
+#        worker = self.depends(Work_D_D)
+
+        sppufunc = self.depends(SpecializedParallelUFunc,
+                                PUFuncDef = ParallelUFuncPosix,
+                                CoreDef = UFuncCore_D_D,
+                                Func = Work_D_D,
+                                FuncName = Work_D_D._name_,
+                                ThreadCount = 2)
 
         # real work
         NULL = self.constant_null(C.void_p)
@@ -83,8 +90,7 @@ class Tester(CDefinition):
                 i += self.constant(C.intp, 1)
 
         # call parallel ufunc
-        parallel_ufunc(worker.cast(C.void_p), ufunc_core.cast(C.void_p),  args,
-                       dims, steps, NULL)
+        sppufunc(args, dims, steps, NULL)
 
         # check error
         outbase = args_double[-1]