diff --git a/ext/gsl_native/function.c b/ext/gsl_native/function.c
index 964e3214..1f96254c 100644
--- a/ext/gsl_native/function.c
+++ b/ext/gsl_native/function.c
@@ -73,13 +73,16 @@ void gsl_function_mark(gsl_function *f)
 static VALUE rb_gsl_function_alloc(int argc, VALUE *argv, VALUE klass)
 {
   gsl_function *f = NULL;
-  VALUE obj;
+  VALUE obj, params;
   f = ALLOC(gsl_function);
   f->function = &rb_gsl_function_f;
-  /*  (VALUE) f->params = rb_ary_new2(2);*/
-  f->params = (void *) rb_ary_new2(2);
-  rb_ary_store((VALUE) f->params, 1, Qnil);
+
+  params = rb_ary_new2(2);
+  rb_ary_store(params, 1, Qnil);
+  f->params = (void *) params;
+
   obj = Data_Wrap_Struct(klass, gsl_function_mark, gsl_function_free, f);
+  RB_GC_GUARD(params);
   rb_gsl_function_set_f(argc, argv, obj);
   return obj;
 }
@@ -338,19 +341,20 @@ static void gsl_function_fdf_mark(gsl_function_fdf *f);
 static VALUE rb_gsl_function_fdf_new(int argc, VALUE *argv, VALUE klass)
 {
   gsl_function_fdf *F = NULL;
-  VALUE ary;
+  VALUE ary, ret;
   size_t i;
   F = ALLOC(gsl_function_fdf);
   F->f = &rb_gsl_function_fdf_f;
   F->df = &rb_gsl_function_fdf_df;
   F->fdf = &rb_gsl_function_fdf_fdf;
   ary = rb_ary_new2(4);
-  /*  (VALUE) F->params = ary;*/
   F->params = (void *) ary;
   rb_ary_store(ary, 2, Qnil);
   rb_ary_store(ary, 3, Qnil);
   for (i = 0; (int) i < argc; i++) setfunc(i, argv, F);
-  return Data_Wrap_Struct(klass, gsl_function_fdf_mark, gsl_function_fdf_free, F);
+  ret = Data_Wrap_Struct(klass, gsl_function_fdf_mark, gsl_function_fdf_free, F);
+  RB_GC_GUARD(ary);
+  return ret;
 }
 
 static void gsl_function_fdf_free(gsl_function_fdf *f)
diff --git a/ext/gsl_native/monte.c b/ext/gsl_native/monte.c
index 3559001a..309d7638 100644
--- a/ext/gsl_native/monte.c
+++ b/ext/gsl_native/monte.c
@@ -91,13 +91,16 @@ static void gsl_monte_function_mark(gsl_monte_function *f)
 static VALUE rb_gsl_monte_function_new(int argc, VALUE *argv, VALUE klass)
 {
   gsl_monte_function *f;
-  VALUE obj;
+  VALUE obj, params;
   f = ALLOC(gsl_monte_function);
   f->f = &rb_gsl_monte_function_f;
-  /*  (VALUE) f->params = rb_ary_new2(2);*/
-  f->params = (void *) rb_ary_new2(2);
-  rb_ary_store((VALUE) f->params, 1, Qnil);
+
+  params = rb_ary_new2(2);
+  rb_ary_store(params, 1, Qnil);
+  f->params = (void *) params;
+
   obj = Data_Wrap_Struct(klass, gsl_monte_function_mark, gsl_monte_function_free, f);
+  RB_GC_GUARD(params);
   rb_gsl_monte_function_set_f(argc, argv, obj);
   return obj;
 }
diff --git a/ext/gsl_native/multimin.c b/ext/gsl_native/multimin.c
index 60aa966c..803e5c00 100644
--- a/ext/gsl_native/multimin.c
+++ b/ext/gsl_native/multimin.c
@@ -75,7 +75,7 @@ static void gsl_multimin_function_fdf_mark(gsl_multimin_function_fdf *F)
 static VALUE rb_gsl_multimin_function_new(int argc, VALUE *argv, VALUE klass)
 {
   gsl_multimin_function *F = NULL;
-  VALUE ary;
+  VALUE ary, ret;
   size_t i;
   F = ALLOC(gsl_multimin_function);
   F->f = &rb_gsl_multimin_function_f;
@@ -98,7 +98,9 @@ static VALUE rb_gsl_multimin_function_new(int argc, VALUE *argv, VALUE klass)
   default:
     rb_raise(rb_eArgError, "wrong number of arguments");
   }
-  return Data_Wrap_Struct(klass, gsl_multimin_function_mark, gsl_multimin_function_free, F);
+  ret = Data_Wrap_Struct(klass, gsl_multimin_function_mark, gsl_multimin_function_free, F);
+  RB_GC_GUARD(ary);
+  return ret;
 }
 
 static void gsl_multimin_function_free(gsl_multimin_function *f)
@@ -209,7 +211,7 @@ static void set_function_fdf(int argc, VALUE *argv, gsl_multimin_function_fdf *F
 static VALUE rb_gsl_multimin_function_fdf_new(int argc, VALUE *argv, VALUE klass)
 {
   gsl_multimin_function_fdf *F = NULL;
-  VALUE ary;
+  VALUE ary, ret;
   F = ALLOC(gsl_multimin_function_fdf);
   F->f = &rb_gsl_multimin_function_fdf_f;
   F->df = &rb_gsl_multimin_function_fdf_df;
@@ -220,7 +222,9 @@ static VALUE rb_gsl_multimin_function_fdf_new(int argc, VALUE *argv, VALUE klass
   rb_ary_store(ary, 2, Qnil);
   rb_ary_store(ary, 3, Qnil);
   set_function_fdf(argc, argv, F);
-  return Data_Wrap_Struct(klass, gsl_multimin_function_fdf_mark, gsl_multimin_function_fdf_free, F);
+  ret = Data_Wrap_Struct(klass, gsl_multimin_function_fdf_mark, gsl_multimin_function_fdf_free, F);
+  RB_GC_GUARD(ary);
+  return ret;
 }
 
 static void gsl_multimin_function_fdf_free(gsl_multimin_function_fdf *f)
diff --git a/ext/gsl_native/multiroots.c b/ext/gsl_native/multiroots.c
index 45675aa8..f5738354 100644
--- a/ext/gsl_native/multiroots.c
+++ b/ext/gsl_native/multiroots.c
@@ -62,7 +62,7 @@ static const gsl_multiroot_fdfsolver_type* get_fdfsolver_type(VALUE t);
 static VALUE rb_gsl_multiroot_function_new(int argc, VALUE *argv, VALUE klass)
 {
   gsl_multiroot_function *F = NULL;
-  VALUE ary;
+  VALUE ary, ret;
   size_t i;
   F = ALLOC(gsl_multiroot_function);
   F->f = &rb_gsl_multiroot_function_f;
@@ -86,7 +86,9 @@ static VALUE rb_gsl_multiroot_function_new(int argc, VALUE *argv, VALUE klass)
     rb_raise(rb_eArgError, "wrong number of arguments");
     break;
   }
-  return Data_Wrap_Struct(klass, gsl_multiroot_function_mark, gsl_multiroot_function_free, F);
+  ret = Data_Wrap_Struct(klass, gsl_multiroot_function_mark, gsl_multiroot_function_free, F);
+  RB_GC_GUARD(ary);
+  return ret;
 }
 
 static void gsl_multiroot_function_free(gsl_multiroot_function *f)
@@ -212,7 +214,7 @@ static void set_function_fdf(int argc, VALUE *argv, gsl_multiroot_function_fdf *
 static VALUE rb_gsl_multiroot_function_fdf_new(int argc, VALUE *argv, VALUE klass)
 {
   gsl_multiroot_function_fdf *F = NULL;
-  VALUE ary;
+  VALUE ary, ret;
   F = ALLOC(gsl_multiroot_function_fdf);
   F->f = &rb_gsl_multiroot_function_fdf_f;
   F->df = &rb_gsl_multiroot_function_fdf_df;
@@ -223,7 +225,9 @@ static VALUE rb_gsl_multiroot_function_fdf_new(int argc, VALUE *argv, VALUE klas
   rb_ary_store(ary, 2, Qnil);
   rb_ary_store(ary, 3, Qnil);
   set_function_fdf(argc, argv, F);
-  return Data_Wrap_Struct(klass, gsl_multiroot_function_fdf_mark, gsl_multiroot_function_fdf_free, F);
+  ret = Data_Wrap_Struct(klass, gsl_multiroot_function_fdf_mark, gsl_multiroot_function_fdf_free, F);
+  RB_GC_GUARD(ary);
+  return ret;
 }
 
 static void gsl_multiroot_function_fdf_free(gsl_multiroot_function_fdf *f)
diff --git a/ext/gsl_native/ndlinear.c b/ext/gsl_native/ndlinear.c
index 92ee1b22..17d873ca 100644
--- a/ext/gsl_native/ndlinear.c
+++ b/ext/gsl_native/ndlinear.c
@@ -94,6 +94,7 @@ static VALUE rb_gsl_multifit_ndlinear_alloc(int argc, VALUE *argv, VALUE klass)
   free((size_t*) N);
 
   wspace = Data_Wrap_Struct(cWorkspace, multifit_ndlinear_mark, gsl_multifit_ndlinear_free, w);
+  RB_GC_GUARD(params);
 
   return wspace;
 }
@@ -317,4 +318,3 @@ void Init_ndlinear(VALUE module)
 }
 
 #endif
-
diff --git a/ext/gsl_native/ntuple.c b/ext/gsl_native/ntuple.c
index fb674ff0..9d5e8f6e 100644
--- a/ext/gsl_native/ntuple.c
+++ b/ext/gsl_native/ntuple.c
@@ -133,21 +133,25 @@ VALUE rb_gsl_ntuple_data(VALUE obj)
 
 /***** select_fn *****/
 
-static gsl_ntuple_select_fn* gsl_ntuple_select_fn_alloc();
 static void gsl_ntuple_select_fn_free(gsl_ntuple_select_fn *ptr);
 int rb_gsl_ntuple_select_fn_f(void *data, void *p);
 static void gsl_ntuple_select_fn_mark(gsl_ntuple_select_fn *ptr);
 
-static gsl_ntuple_select_fn* gsl_ntuple_select_fn_alloc()
+static VALUE gsl_ntuple_select_fn_alloc(VALUE klass)
 {
+  VALUE params, ret;
   gsl_ntuple_select_fn *ptr = NULL;
   ptr = ALLOC(gsl_ntuple_select_fn);
   if (ptr == NULL) rb_raise(rb_eRuntimeError, "malloc failed");
   ptr->function = &rb_gsl_ntuple_select_fn_f;
-  /*  (VALUE) ptr->params = rb_ary_new2(3);*/
-  ptr->params = (void *) rb_ary_new2(3);
-  rb_ary_store((VALUE) ptr->params, 1, Qnil);
-  return ptr;
+
+  params = rb_ary_new2(3);
+  rb_ary_store(params, 1, Qnil);
+  ptr->params = (void *) params;
+
+  ret = Data_Wrap_Struct(klass, gsl_ntuple_select_fn_mark, gsl_ntuple_select_fn_free, ptr);
+  RB_GC_GUARD(params);
+  return ret;
 }
 
 static void gsl_ntuple_select_fn_free(gsl_ntuple_select_fn *ptr)
@@ -244,30 +248,32 @@ static VALUE rb_gsl_ntuple_select_fn_set_params(int argc, VALUE *argv, VALUE obj
 
 static VALUE rb_gsl_ntuple_select_fn_new(int argc, VALUE *argv, VALUE klass)
 {
-  gsl_ntuple_select_fn *F = NULL;
-  VALUE ff;
-  F = gsl_ntuple_select_fn_alloc();
-  ff = Data_Wrap_Struct(klass, gsl_ntuple_select_fn_mark, gsl_ntuple_select_fn_free, F);
-  rb_gsl_ntuple_select_fn_set_f(argc, argv, ff);
-  return ff;
+  VALUE F;
+  F = gsl_ntuple_select_fn_alloc(klass);
+  rb_gsl_ntuple_select_fn_set_f(argc, argv, F);
+  return F;
 }
 
 /***** value_fn *****/
-static gsl_ntuple_value_fn* gsl_ntuple_value_fn_alloc();
 static void gsl_ntuple_value_fn_free(gsl_ntuple_value_fn *ptr);
 static double rb_gsl_ntuple_value_fn_f(void *data, void *p);
 static void gsl_ntuple_value_fn_mark(gsl_ntuple_value_fn *ptr);
 
-static gsl_ntuple_value_fn* gsl_ntuple_value_fn_alloc()
+static VALUE gsl_ntuple_value_fn_alloc(VALUE klass)
 {
+  VALUE params, ret;
   gsl_ntuple_value_fn *ptr = NULL;
   ptr = ALLOC(gsl_ntuple_value_fn);
   if (ptr == NULL) rb_raise(rb_eRuntimeError, "malloc failed");
   ptr->function = &rb_gsl_ntuple_value_fn_f;
-  /*  (VALUE) ptr->params = rb_ary_new2(3);*/
-  ptr->params = (void *) rb_ary_new2(3);
+
+  params = rb_ary_new2(3);
+  ptr->params = (void *) params;
   rb_ary_store((VALUE) ptr->params, 1, Qnil);
-  return ptr;
+
+  ret = Data_Wrap_Struct(klass, gsl_ntuple_value_fn_mark, gsl_ntuple_value_fn_free, ptr);
+  RB_GC_GUARD(params);
+  return ret;
 }
 
 static void gsl_ntuple_value_fn_mark(gsl_ntuple_value_fn *ptr)
@@ -362,12 +368,10 @@ static VALUE rb_gsl_ntuple_value_fn_set_params(int argc, VALUE *argv, VALUE obj)
 
 static VALUE rb_gsl_ntuple_value_fn_new(int argc, VALUE *argv, VALUE klass)
 {
-  gsl_ntuple_value_fn *F = NULL;
-  VALUE ff;
-  F = gsl_ntuple_value_fn_alloc();
-  ff = Data_Wrap_Struct(klass, gsl_ntuple_value_fn_mark, gsl_ntuple_value_fn_free, F);
-  rb_gsl_ntuple_value_fn_set_f(argc, argv, ff);
-  return ff;
+  VALUE F;
+  F = gsl_ntuple_value_fn_alloc(klass);
+  rb_gsl_ntuple_value_fn_set_f(argc, argv, F);
+  return F;
 }
 
 /* singleton method */
diff --git a/ext/gsl_native/ool.c b/ext/gsl_native/ool.c
index ea8ade4b..b67b599d 100644
--- a/ext/gsl_native/ool.c
+++ b/ext/gsl_native/ool.c
@@ -448,6 +448,7 @@ static VALUE rb_ool_conmin_function_alloc(int argc, VALUE *argv, VALUE klass)
   rb_ary_store(ary, 4, Qnil);  /* params */
 //  set_functions(argc, argv, F);
   obj = Data_Wrap_Struct(klass, rb_ool_conmin_function_mark, free, F);
+  RB_GC_GUARD(ary);
   rb_ool_conmin_function_set(argc, argv, obj);
   return obj;
 }