diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0efb933..a6c0313 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -7,6 +7,8 @@ else()
 endif()
 project(c-capnproto LANGUAGES ${languages})
 
+configure_file(c-capnproto.pc.in c-capnproto.pc @ONLY)
+
 include(CTest)
 
 # set(CMAKE_C_STANDARD 11)
@@ -161,6 +163,7 @@ endif()
 
 option(C_CAPNPROTO_ENABLE_INSTALL "Add instructions for 'cmake --install' of CapnC_Runtime library and capnpc-c executable" ON)
 if(C_CAPNPROTO_ENABLE_INSTALL)
+    set(CMAKE_INSTALL_LIBDIR ${CMAKE_INSTALL_PREFIX}/lib)
     install(TARGETS CapnC_Runtime capnpc-c
             EXPORT CapnC)
     install(EXPORT CapnC
@@ -168,6 +171,8 @@ if(C_CAPNPROTO_ENABLE_INSTALL)
             NAMESPACE CapnC::
             FILE CapnCConfig.cmake)
     install(FILES lib/capnp_c.h TYPE INCLUDE)
+    install(FILES build/c-capnproto.pc 
+	    DESTINATION "${CMAKE_INSTALL_LIBDIR}/pkgconfig")
 endif()
 
 add_subdirectory(examples/book)
diff --git a/c-capnproto.pc.in b/c-capnproto.pc.in
index 45bd6c7..c5409b5 100644
--- a/c-capnproto.pc.in
+++ b/c-capnproto.pc.in
@@ -1,12 +1,12 @@
-prefix=@prefix@
-exec_prefix=@exec_prefix@
-libdir=@libdir@
-bindir=@bindir@
-includedir=@includedir@
+prefix=@CMAKE_INSTALL_PREFIX@
+exec_prefix=${prefix}
+libdir=${prefix}/lib
+bindir=${prefix}/bin
+includedir=${prefix}/include
 codegen=${bindir}/capnpc-c
 
 Name: c-capnproto
 Description: Cap'n Proto C bindings
 Version: @PACKAGE_VERSION@
-Libs: -L${libdir} -lcapnp_c
+Libs: -L${libdir} -lCapnC_Runtime
 Cflags: -I${includedir}
diff --git a/compiler/capnpc-c.c b/compiler/capnpc-c.c
index 8d98544..c8eb6f4 100644
--- a/compiler/capnpc-c.c
+++ b/compiler/capnpc-c.c
@@ -887,15 +887,25 @@ static void mk_simple_list_decoder(struct str *func, const char *tab,
     str_add(func, tab, -1);
     str_addf(func, "\tnc_ = s->%s.len;\n", svar);
     str_add(func, tab, -1);
-    str_addf(func, "\td->%s = (char **)calloc(nc_, sizeof(char *));\n", dvar);
+    str_addf(func, "\tif (nc_ == 0) {\n");
     str_add(func, tab, -1);
-    str_addf(func, "\tfor(i_ = 0; i_ < nc_; i_ ++) {\n");
+    str_addf(func, "\t\td->%s = NULL;\n", dvar);
+    str_add(func, tab, -1);
+    str_addf(func, "\t}\n");
+    str_add(func, tab, -1);
+    str_addf(func, "\telse {\n");
+    str_add(func, tab, -1);
+    str_addf(func, "\t\td->%s = (char **)calloc(nc_, sizeof(char *));\n", dvar);
+    str_add(func, tab, -1);
+    str_addf(func, "\t\tfor(i_ = 0; i_ < nc_; i_ ++) {\n");
     str_add(func, tab, -1);
     str_addf(func,
-             "\t\tcapn_text text_ = capn_get_text(s->%s, i_, capn_val0);\n",
+             "\t\t\tcapn_text text_ = capn_get_text(s->%s, i_, capn_val0);\n",
              svar);
     str_add(func, tab, -1);
-    str_addf(func, "\t\td->%s[i_] = strdup(text_.str);\n", dvar);
+    str_addf(func, "\t\t\td->%s[i_] = strdup(text_.str);\n", dvar);
+    str_add(func, tab, -1);
+    str_addf(func, "\t\t}\n");
     str_add(func, tab, -1);
     str_addf(func, "\t}\n");
   } else {
@@ -903,14 +913,23 @@ static void mk_simple_list_decoder(struct str *func, const char *tab,
     str_addf(func, "\tcapn_resolve(&(s->%s.p));\n", svar);
     str_add(func, tab, -1);
     str_addf(func, "\tnc_ = s->%s.p.len;\n", svar);
-
     str_add(func, tab, -1);
-    str_addf(func, "\td->%s = (%s *)calloc(nc_, sizeof(%s));\n", dvar,
+    str_addf(func, "\tif (nc_ == 0) {\n");
+    str_add(func, tab, -1);
+    str_addf(func, "\t\td->%s = NULL;\n", dvar);
+    str_add(func, tab, -1);
+    str_addf(func, "\t}\n");
+    str_add(func, tab, -1);
+    str_addf(func, "\telse {\n");
+    str_add(func, tab, -1);
+    str_addf(func, "\t\td->%s = (%s *)calloc(nc_, sizeof(%s));\n", dvar,
              list_type, list_type);
     str_add(func, tab, -1);
-    str_addf(func, "\tfor(i_ = 0; i_ < nc_; i_ ++) {\n");
+    str_addf(func, "\t\tfor(i_ = 0; i_ < nc_; i_ ++) {\n");
     str_add(func, tab, -1);
-    str_addf(func, "\t\td->%s[i_] = capn_%s(s->%s, i_);\n", dvar, getf, svar);
+    str_addf(func, "\t\t\td->%s[i_] = capn_%s(s->%s, i_);\n", dvar, getf, svar);
+    str_add(func, tab, -1);
+    str_addf(func, "\t\t}\n");
     str_add(func, tab, -1);
     str_addf(func, "\t}\n");
   }
@@ -921,6 +940,33 @@ static void mk_simple_list_decoder(struct str *func, const char *tab,
   str_addf(func, "}\n");
 }
 
+static void mk_simple_list_free(struct str *func, const char *tab,
+                                const char *list_type, const char *getf,
+                                const char *dvar, const char *cvar,
+                                const char *svar) {
+  str_add(func, tab, -1);
+  str_addf(func, "if (1) {\n");
+  str_add(func, tab, -1);
+  str_addf(func, "\tint i_, nc_ = d->%s;\n", cvar);
+  str_add(func, tab, -1);
+  str_addf(func, "\tcapnp_use(i_);capnp_use(nc_);\n");
+  if (strcmp(list_type, "text") == 0) {
+    str_add(func, tab, -1);
+    str_addf(func, "\tfor(i_ = 0; i_ < nc_; i_ ++) {\n");
+    str_add(func, tab, -1);
+    str_addf(func, "\t\tif (d->%s[i_] == NULL) continue;\n", dvar);
+    str_add(func, tab, -1);
+    str_addf(func, "\t\tfree(d->%s[i_]);\n", dvar);
+    str_add(func, tab, -1);
+    str_addf(func, "\t}\n");
+  }
+
+  str_add(func, tab, -1);
+  str_addf(func, "\tfree(d->%s);\n", dvar);
+  str_add(func, tab, -1);
+  str_addf(func, "}\n");
+}
+
 static void gen_call_list_encoder(capnp_ctx_t *ctx, struct str *func,
                                   struct Type *type, const char *tab,
                                   const char *var, const char *countvar,
@@ -1039,6 +1085,77 @@ static void gen_call_list_decoder(capnp_ctx_t *ctx, struct str *func,
   }
 }
 
+static void gen_call_list_free(capnp_ctx_t *ctx, struct str *func,
+                               struct Type *type, const char *tab,
+                               const char *var, const char *countvar,
+                               const char *var2) {
+  char *t = NULL;
+  struct node *n = NULL;
+
+  str_add(func, tab, -1);
+
+  switch (type->which) {
+  case Type__bool:
+    t = "uint8_t";
+    mk_simple_list_free(func, tab, t, "get1", var, countvar, var2);
+    break;
+  case Type_int8:
+  case Type_uint8:
+    if (type->which == Type_int8) {
+      t = "int8_t";
+    } else {
+      t = "uint8_t";
+    }
+    mk_simple_list_free(func, tab, t, "get8", var, countvar, var2);
+    break;
+  case Type_int16:
+  case Type_uint16:
+    if (type->which == Type_int16) {
+      t = "int16_t";
+    } else {
+      t = "uint16_t";
+    }
+    mk_simple_list_free(func, tab, t, "get16", var, countvar, var2);
+    break;
+  case Type_int32:
+  case Type_uint32:
+  case Type_float32:
+    if (type->which == Type_int32) {
+      t = "int32_t";
+    } else if (type->which == Type_uint32) {
+      t = "uint32_t";
+    } else {
+      t = "float";
+    }
+    mk_simple_list_free(func, tab, t, "get32", var, countvar, var2);
+    break;
+  case Type_int64:
+  case Type_uint64:
+  case Type_float64:
+    if (type->which == Type_int64) {
+      t = "int64_t";
+    } else if (type->which == Type_uint64) {
+      t = "uint64_t";
+    } else {
+      t = "double";
+    }
+    mk_simple_list_free(func, tab, t, "get64", var, countvar, var2);
+    break;
+
+  case Type_text:
+    mk_simple_list_free(func, tab, "text", NULL, var, countvar, var2);
+    break;
+  case Type__struct:
+    n = find_node(ctx, type->_struct.typeId);
+    if (n != NULL) {
+      char *dtypename = n->name.str;
+
+      str_addf(func, "free_%s_list(d->%s, d->%s);\n", dtypename, countvar, var);
+    }
+    break;
+  }
+}
+
 static void encode_member(capnp_ctx_t *ctx, struct str *func, struct field *f,
                           const char *tab, const char *var, const char *var2) {
   struct Type list_type;
@@ -1214,6 +1331,93 @@ static void decode_member(capnp_ctx_t *ctx, struct str *func, struct field *f,
   }
 }
 
+static void free_member(capnp_ctx_t *ctx, struct str *func, struct field *f,
+                        const char *tab, const char *var, const char *var2) {
+  struct Type list_type;
+  struct node *n = NULL;
+
+  if (f->v.t.which == Type__void) {
+    return;
+  }
+
+  if (var2 == NULL) {
+    var2 = var;
+  }
+
+  switch (f->v.t.which) {
+  case Type__bool:
+  case Type_int8:
+  case Type_int16:
+  case Type_int32:
+  case Type_int64:
+  case Type_uint8:
+  case Type_uint16:
+  case Type_uint32:
+  case Type_uint64:
+  case Type_float32:
+  case Type_float64:
+  case Type__enum:
+    break;
+  case Type_text:
+    str_add(func, tab, -1);
+    str_addf(func, "if (d->%s != NULL) {\n", var2);
+    str_add(func, tab, -1);
+    str_addf(func, "\tfree(d->%s);\n", var2);
+    str_add(func, tab, -1);
+    str_addf(func, "}\n");
+    break;
+  case Type__struct:
+    n = find_node(ctx, f->v.t._struct.typeId);
+    if (n != NULL) {
+      str_add(func, tab, -1);
+      str_addf(func, "free_%s_ptr(&(d->%s));\n", n->name.str, var2);
+    }
+    break;
+  case Type__list:
+    read_Type(&list_type, f->v.t._list.elementType);
+    if (list_type.which != Type__void) {
+      char *name = NULL;
+      char *ncount = NULL;
+      char buf[256];
+
+      name = (char *)get_mapname(f->f.annotations);
+      if (name == NULL) {
+        var2 = var;
+      } else {
+        var2 = name;
+      }
+
+      ncount = (char *)get_maplistcount(f->f.annotations);
+      if (ncount != NULL) {
+        sprintf(buf, "%s", ncount);
+      } else {
+        char buf2[256];
+        char *p;
+
+        strcpy(buf2, var2);
+        p = strchr(buf2, '.');
+        if (p != NULL) {
+          *p = 0x0;
+          p++;
+        }
+
+        strcpy(buf, buf2);
+        if (p != NULL) {
+          strcat(buf, ".");
+          sprintf(&buf[strlen(buf)], "n_%s", p);
+        }
+      }
+
+      gen_call_list_free(ctx, func, &list_type, tab, var2, buf, var);
+    }
+    break;
+  default:
+    str_add(func, tab, -1);
+    str_addf(func, "\t /* %s %s */\n", var2, var);
+    break;
+  }
+}
+
 void mk_struct_list_encoder(capnp_ctx_t *ctx, struct node *n) {
   if (n == NULL) {
     return;
@@ -1231,14 +1435,14 @@ void mk_struct_list_encoder(capnp_ctx_t *ctx, struct node *n) {
 
     str_addf(&(ctx->SRC),
              "void encode_%s_list(struct capn_segment *cs, %s_list *l,int "
-             "count,%s *s) {\n",
+             "count,%s **s) {\n",
              n->name.str, n->name.str, buf);
     str_addf(&(ctx->SRC), "\t%s_list lst;\n", n->name.str);
     str_addf(&(ctx->SRC), "\tint i;\n");
     str_addf(&(ctx->SRC), "\tlst = new_%s_list(cs, count);\n", n->name.str);
     str_addf(&(ctx->SRC), "\tfor(i = 0; i < count; i ++) {\n");
     str_addf(&(ctx->SRC), "\t\tstruct %s d;\n", n->name.str);
-    str_addf(&(ctx->SRC), "\t\tencode_%s(cs, &d, &(s[i]));\n", n->name.str);
+    str_addf(&(ctx->SRC), "\t\tencode_%s(cs, &d, s[i]);\n", n->name.str);
     str_addf(&(ctx->SRC), "\t\tset_%s(&d, lst, i);\n", n->name.str);
     str_addf(&(ctx->SRC), "\t}\n");
     str_addf(&(ctx->SRC), "\t(*l) = lst;\n");
@@ -1268,15 +1472,17 @@ void mk_struct_ptr_encoder(capnp_ctx_t *ctx, struct node *n) {
            n->name.str, n->name.str, buf);
   str_addf(&(ctx->SRC), "\t%s_ptr ptr;\n", n->name.str);
   str_addf(&(ctx->SRC), "\tstruct %s d;\n", n->name.str);
-  str_addf(&(ctx->SRC), "\t%s zero_ = {0}; \n", buf);
   str_addf(&(ctx->SRC), "\tptr = new_%s(cs);\n", n->name.str);
   str_addf(&(ctx->SRC), "\tif (s == NULL) {\n");
-  str_addf(&(ctx->SRC), "\t\ts = &zero_;\n");
+  str_addf(&(ctx->SRC), "\t\tptr.p = capn_null;\n");
+  str_addf(&(ctx->SRC), "\t}\n");
+  str_addf(&(ctx->SRC), "\telse{\n");
+  str_addf(&(ctx->SRC), "\t\tencode_%s(cs, &d, s);\n", n->name.str);
+  str_addf(&(ctx->SRC), "\t\twrite_%s(&d, ptr);\n", n->name.str);
   str_addf(&(ctx->SRC), "\t}\n");
-  str_addf(&(ctx->SRC), "\tencode_%s(cs, &d, s);\n", n->name.str);
-  str_addf(&(ctx->SRC), "\twrite_%s(&d, ptr);\n", n->name.str);
   str_addf(&(ctx->SRC), "\t(*p) = ptr;\n");
   str_addf(&(ctx->SRC), "}\n");
+  ctx->g_nullused = 1;
 }
 
 void mk_struct_list_decoder(capnp_ctx_t *ctx, struct node *n) {
@@ -1295,18 +1501,26 @@ void mk_struct_list_decoder(capnp_ctx_t *ctx, struct node *n) {
     }
 
     str_addf(&(ctx->SRC),
-             "void decode_%s_list(int *pcount, %s **d, %s_list list) {\n",
+             "void decode_%s_list(int *pcount, %s ***d, %s_list list) {\n",
              n->name.str, buf, n->name.str);
     str_addf(&(ctx->SRC), "\tint i;\n");
     str_addf(&(ctx->SRC), "\tint nc;\n");
-    str_addf(&(ctx->SRC), "\t%s *ptr;\n", buf);
+    str_addf(&(ctx->SRC), "\t%s **ptr;\n", buf);
     str_addf(&(ctx->SRC), "\tcapn_resolve(&(list.p));\n");
     str_addf(&(ctx->SRC), "\tnc = list.p.len;\n");
-    str_addf(&(ctx->SRC), "\tptr = (%s *)calloc(nc, sizeof(%s));\n", buf, buf);
+    str_addf(&(ctx->SRC), "\tif (nc == 0) {\n");
+    str_addf(&(ctx->SRC), "\t\t(*d) = NULL;\n");
+    str_addf(&(ctx->SRC), "\t\t(*pcount) = 0;\n");
+    str_addf(&(ctx->SRC), "\t\treturn;\n");
+    str_addf(&(ctx->SRC), "\t}\n");
+    str_addf(&(ctx->SRC), "\tptr = (%s **)calloc(nc, sizeof(%s *));\n", buf,
+             buf);
     str_addf(&(ctx->SRC), "\tfor(i = 0; i < nc; i ++) {\n");
     str_addf(&(ctx->SRC), "\t\tstruct %s s;\n", n->name.str);
     str_addf(&(ctx->SRC), "\t\tget_%s(&s, list, i);\n", n->name.str);
-    str_addf(&(ctx->SRC), "\t\tdecode_%s(&(ptr[i]), &s);\n", n->name.str);
+    str_addf(&(ctx->SRC), "\t\tptr[i] = (%s *)calloc(1, sizeof(%s));\n", buf,
+             buf);
+    str_addf(&(ctx->SRC), "\t\tdecode_%s(ptr[i], &s);\n", n->name.str);
     str_addf(&(ctx->SRC), "\t}\n");
     str_addf(&(ctx->SRC), "\t(*d) = ptr;\n");
     str_addf(&(ctx->SRC), "\t(*pcount) = nc;\n");
@@ -1335,10 +1549,71 @@ void mk_struct_ptr_decoder(capnp_ctx_t *ctx, struct node *n) {
            "%s_ptr p) {\n",
            n->name.str, buf, n->name.str);
   str_addf(&(ctx->SRC), "\tstruct %s s;\n", n->name.str);
+  str_addf(&(ctx->SRC), "\tcapn_resolve(&(p.p));\n");
+  str_addf(&(ctx->SRC), "\tif (p.p.type == CAPN_NULL) {\n");
+  str_addf(&(ctx->SRC), "\t\t(*d) = NULL;\n");
+  str_addf(&(ctx->SRC), "\t\treturn;\n");
+  str_addf(&(ctx->SRC), "\t}\n");
   str_addf(&(ctx->SRC), "\t*d = (%s *)calloc(1, sizeof(%s));\n", buf, buf);
   str_addf(&(ctx->SRC), "\tread_%s(&s, p);\n", n->name.str);
   str_addf(&(ctx->SRC), "\tdecode_%s(*d, &s);\n", n->name.str);
   str_addf(&(ctx->SRC), "}\n");
+  ctx->g_nullused = 1;
+}
+
+void mk_struct_list_free(capnp_ctx_t *ctx, struct node *n) {
+  if (n == NULL) {
+    return;
+  }
+
+  if (1) {
+    char *mapname = (char *)get_mapname(n->n.annotations);
+    char buf[256];
+
+    if (mapname == NULL) {
+      sprintf(buf, "struct %s_", n->name.str);
+    } else {
+      strcpy(buf, mapname);
+    }
+
+    str_addf(&(ctx->SRC), "void free_%s_list(int pcount, %s **d) {\n",
+             n->name.str, buf);
+    str_addf(&(ctx->SRC), "\tint i;\n");
+    str_addf(&(ctx->SRC), "\tint nc = pcount;\n");
+    str_addf(&(ctx->SRC), "\t%s **ptr = d;\n", buf);
+    str_addf(&(ctx->SRC), "\tif (ptr == NULL) return;\n");
+    str_addf(&(ctx->SRC), "\tfor(i = 0; i < nc; i ++) {\n");
+    str_addf(&(ctx->SRC), "\t\tif(ptr[i] == NULL) continue;\n");
+    str_addf(&(ctx->SRC), "\t\tfree_%s(ptr[i]);\n", n->name.str);
+    str_addf(&(ctx->SRC), "\t\tfree(ptr[i]);\n");
+    str_addf(&(ctx->SRC), "\t}\n");
+    str_addf(&(ctx->SRC), "\tfree(ptr);\n");
+    str_addf(&(ctx->SRC), "}\n");
+  }
+}
+
+void mk_struct_ptr_free(capnp_ctx_t *ctx, struct node *n) {
+  char *mapname;
+  char buf[256];
+
+  if (n == NULL) {
+    return;
+  }
+
+  mapname = (char *)get_mapname(n->n.annotations);
+
+  if (mapname == NULL) {
+    sprintf(buf, "struct %s_", n->name.str);
+  } else {
+    strcpy(buf, mapname);
+  }
+
+  str_addf(&(ctx->SRC), "void free_%s_ptr(%s **d){\n", n->name.str, buf);
+  str_addf(&(ctx->SRC), "\tif((*d) == NULL) return;\n");
+  str_addf(&(ctx->SRC), "\tfree_%s(*d);\n", n->name.str);
+  str_addf(&(ctx->SRC), "\tfree(*d);\n");
+  str_addf(&(ctx->SRC), "\t(*d) = NULL;\n");
+  str_addf(&(ctx->SRC), "}\n");
 }
 
 struct strings {
@@ -1348,6 +1623,7 @@ struct strings {
   struct str set;
   struct str encoder;
   struct str decoder;
+  struct str freeup;
   struct str enums;
   struct str decl;
   struct str var;
@@ -1514,6 +1790,8 @@ static void union_block(capnp_ctx_t *ctx, struct strings *s, struct field *f,
     str_addf(&s->encoder, "%sbreak;\n", s->ftab.str);
     decode_member(ctx, &s->decoder, f, s->ftab.str, var1, var2);
     str_addf(&s->decoder, "%sbreak;\n", s->ftab.str);
+    free_member(ctx, &s->freeup, f, s->ftab.str, var1, var2);
+    str_addf(&s->freeup, "%sbreak;\n", s->ftab.str);
   }
   str_setlen(&s->ftab, s->ftab.len - 1);
 }
@@ -1546,6 +1824,8 @@ static void union_cases(capnp_ctx_t *ctx, struct strings *s, struct node *n,
                field_name(f));
       str_addf(&s->decoder, "%scase %s_%s:\n", s->ftab.str, n->name.str,
                field_name(f));
+      str_addf(&s->freeup, "%scase %s_%s:\n", s->ftab.str, n->name.str,
+               field_name(f));
     }
 
     if (u) {
@@ -1571,11 +1851,13 @@ static void declare_slot(struct strings *s, struct field *f) {
 
 static void define_group(capnp_ctx_t *ctx, struct strings *s, struct node *n,
                          const char *group_name, bool enclose_unions,
-                         const char *extattr, const char *extattr_space);
+                         const char *extattr, const char *extattr_space,
+                         const char *uniontag);
 
 static void do_union(capnp_ctx_t *ctx, struct strings *s, struct node *n,
                      struct field *first_field, const char *union_name,
-                     const char *extattr, const char *extattr_space) {
+                     const char *extattr, const char *extattr_space,
+                     const char *uniontag) {
   int tagoff = 2 * n->n._struct.discriminantOffset;
   struct field *f;
   static struct str tag = STR_INIT;
@@ -1615,6 +1897,7 @@ static void do_union(capnp_ctx_t *ctx, struct strings *s, struct node *n,
 
     str_addf(&s->encoder, "%sswitch (%s) {\n", s->ftab.str, var);
     str_addf(&s->decoder, "%sswitch (%s) {\n", s->ftab.str, tag.str);
+    str_addf(&s->freeup, "%sswitch (%s) {\n", s->ftab.str, uniontag);
   }
 
   /* if we have a bunch of the same C type with zero defaults, we
@@ -1658,12 +1941,13 @@ static void do_union(capnp_ctx_t *ctx, struct strings *s, struct node *n,
       // own struct so that its members do not overwrite its own
       // discriminant.
       define_group(ctx, s, f->group, field_name(f), true, extattr,
-                   extattr_space);
+                   extattr_space, uniontag);
       str_addf(&s->get, "%sbreak;\n", s->ftab.str);
       str_addf(&s->set, "%sbreak;\n", s->ftab.str);
       if (ctx->g_codecgen) {
         str_addf(&s->encoder, "%sbreak;\n", s->ftab.str);
         str_addf(&s->decoder, "%sbreak;\n", s->ftab.str);
+        str_addf(&s->freeup, "%sbreak;\n", s->ftab.str);
       }
       str_setlen(&s->ftab, s->ftab.len - 1);
       break;
@@ -1680,6 +1964,8 @@ static void do_union(capnp_ctx_t *ctx, struct strings *s, struct node *n,
                    field_name(f));
           str_addf(&s->decoder, "%scase %s_%s:\n", s->ftab.str, n->name.str,
                    field_name(f));
+          str_addf(&s->freeup, "%scase %s_%s:\n", s->ftab.str, n->name.str,
+                   field_name(f));
         }
         union_block(
             ctx, s, f,
@@ -1711,6 +1997,8 @@ static void do_union(capnp_ctx_t *ctx, struct strings *s, struct node *n,
              s->ftab.str, s->ftab.str);
     str_addf(&s->decoder, "%sdefault:\n%s\tbreak;\n%s}\n", s->ftab.str,
              s->ftab.str, s->ftab.str);
+    str_addf(&s->freeup, "%sdefault:\n%s\tbreak;\n%s}\n", s->ftab.str,
+             s->ftab.str, s->ftab.str);
   }
 
   str_addf(&enums, "\n};\n");
@@ -1734,11 +2022,16 @@ static void define_field(capnp_ctx_t *ctx, struct strings *s, struct field *f,
                     get_mapname(f->f.annotations));
       decode_member(ctx, &s->decoder, f, s->ftab.str, field_name(f),
                     get_mapname(f->f.annotations));
+      free_member(ctx, &s->freeup, f, s->ftab.str, field_name(f),
+                  get_mapname(f->f.annotations));
     }
     break;
 
   case Field_group:
     if (ctx->g_codecgen) {
+      char uniontagvar[256];
+
+      memset(uniontagvar, 0x0, sizeof(uniontagvar));
       if (f->group != NULL) {
         int flen = capn_len(f->group->n._struct.fields);
         int ulen = f->group->n._struct.discriminantCount;
@@ -1758,12 +2051,16 @@ static void define_field(capnp_ctx_t *ctx, struct strings *s, struct field *f,
                      buf);
             str_addf(&s->decoder, "\td->%s = s->%s_which;\n", buf,
                      field_name(f));
+            sprintf(uniontagvar, "d->%s", buf);
           }
         }
       }
+      define_group(ctx, s, f->group, field_name(f), false, extattr,
+                   extattr_space, uniontagvar);
+    } else {
+      define_group(ctx, s, f->group, field_name(f), false, extattr,
+                   extattr_space, NULL);
     }
-    define_group(ctx, s, f->group, field_name(f), false, extattr,
-                 extattr_space);
     break;
   }
 }
@@ -1812,7 +2109,8 @@ static void define_encode_function(capnp_ctx_t *ctx, struct node *node,
                                    const char *extattr_space) {}
 static void define_group(capnp_ctx_t *ctx, struct strings *s, struct node *n,
                          const char *group_name, bool enclose_unions,
-                         const char *extattr, const char *extattr_space) {
+                         const char *extattr, const char *extattr_space,
+                         const char *uniontag) {
   struct field *f;
   int flen = capn_len(n->n._struct.fields);
   int ulen = n->n._struct.discriminantCount;
@@ -1877,7 +2175,7 @@ static void define_group(capnp_ctx_t *ctx, struct strings *s, struct node *n,
     const bool keep_union_name = named_union && !enclose_unions;
 
     do_union(ctx, s, n, f, keep_union_name ? group_name : NULL, extattr,
-             extattr_space);
+             extattr_space, uniontag);
 
     while (f < n->fields + flen && in_union(f))
       f++;
@@ -1914,6 +2212,7 @@ static void define_struct(capnp_ctx_t *ctx, struct node *n, const char *extattr,
   str_reset(&s.set);
   str_reset(&s.encoder);
   str_reset(&s.decoder);
+  str_reset(&s.freeup);
   str_reset(&s.enums);
   str_reset(&s.decl);
   str_reset(&s.var);
@@ -1940,7 +2239,7 @@ static void define_struct(capnp_ctx_t *ctx, struct node *n, const char *extattr,
     }
   }
 
-  define_group(ctx, &s, n, NULL, false, extattr, extattr_space);
+  define_group(ctx, &s, n, NULL, false, extattr, extattr_space, NULL);
 
   str_add(&(ctx->HDR), s.enums.str, s.enums.len);
 
@@ -2041,6 +2340,9 @@ static void define_struct(capnp_ctx_t *ctx, struct node *n, const char *extattr,
              n->name.str, buf, n->name.str);
     str_addf(&(ctx->SRC), "%s\n", s.decoder.str);
     str_addf(&(ctx->SRC), "}\n");
+    str_addf(&(ctx->SRC), "\nvoid free_%s(%s *d) {\n", n->name.str, buf);
+    str_addf(&(ctx->SRC), "%s\n", s.freeup.str);
+    str_addf(&(ctx->SRC), "}\n");
   }
 
   str_add(&(ctx->SRC), s.pub_get.str, s.pub_get.len);
@@ -2101,15 +2403,19 @@ static void mk_codec_declares(capnp_ctx_t *ctx, const char *n1,
            "void encode_%s(struct capn_segment *,struct %s *, %s *);\n", n1, n1,
            n2);
   str_addf(&(ctx->HDR), "void decode_%s(%s *, struct %s *);\n", n1, n2, n1);
-  str_addf(&(ctx->HDR),
-           "void encode_%s_list(struct capn_segment *,%s_list *, int, %s *);\n",
-           n1, n1, n2);
-  str_addf(&(ctx->HDR), "void decode_%s_list(int *, %s **, %s_list);\n", n1, n2,
-           n1);
+  str_addf(&(ctx->HDR), "void free_%s(%s *);\n", n1, n2);
+  str_addf(
+      &(ctx->HDR),
+      "void encode_%s_list(struct capn_segment *,%s_list *, int, %s **);\n", n1,
+      n1, n2);
+  str_addf(&(ctx->HDR), "void decode_%s_list(int *, %s ***, %s_list);\n", n1,
+           n2, n1);
+  str_addf(&(ctx->HDR), "void free_%s_list(int, %s **);\n", n1, n2);
   str_addf(&(ctx->HDR),
            "void encode_%s_ptr(struct capn_segment*, %s_ptr *, %s *);\n", n1,
            n1, n2);
   str_addf(&(ctx->HDR), "void decode_%s_ptr(%s **, %s_ptr);\n", n1, n2, n1);
+  str_addf(&(ctx->HDR), "void free_%s_ptr(%s **);\n", n1, n2);
 }
 static void declare_codec(capnp_ctx_t *ctx, struct node *file_node) {
   struct node *n;
@@ -2432,6 +2738,8 @@ int ctx_gen(capnp_ctx_t *ctx) {
         mk_struct_ptr_encoder(ctx, n);
         mk_struct_list_decoder(ctx, n);
         mk_struct_ptr_decoder(ctx, n);
+        mk_struct_list_free(ctx, n);
+        mk_struct_ptr_free(ctx, n);
       }
     }
 
diff --git a/examples/book/book.capnp b/examples/book/book.capnp
index c9c13ac..1e759de 100644
--- a/examples/book/book.capnp
+++ b/examples/book/book.capnp
@@ -20,6 +20,13 @@ struct Nulldata $C.mapname("nulldata_t") {
   null  @0: UInt32 $C.mapname("null_");
 }
 
+struct Buy $C.mapname("buy_t") {
+  from  @0: Text;
+  u :union $C.mapname("u") $C.mapuniontag("with_recipe") {
+    norecipe   @1: Void;
+    recipeAddr @2: Text $C.mapname("recipe_addr");
+  }
+}
 struct Book $C.mapname("book_t") {
   title   @0: Text;
   authors @1: List(Text) $C.mapname("authors") $C.maplistcount("n_authors");
@@ -29,7 +36,7 @@ struct Book $C.mapname("book_t") {
   magic1  @2: List(UInt32) $C.mapname("magic_1") $C.maplistcount("n_magic1");
   description @8: Text;
   acquire :union $C.mapuniontag("acquire_method") {
-    buy   @3: Text;
+    buy   @3: Buy;
     donation @4: Text;
   }
 }
diff --git a/examples/book/book.h b/examples/book/book.h
index 2c6bd77..91a9b9f 100644
--- a/examples/book/book.h
+++ b/examples/book/book.h
@@ -6,36 +6,44 @@
 #include <string.h>
 
 typedef struct {
-    char *caption;
-    int32_t start;
-    int32_t end;
+  char *caption;
+  int32_t start;
+  int32_t end;
 } chapter_t;
 
 typedef struct {
-    uint64_t isbn;
-    uint32_t year;
+  uint64_t isbn;
+  uint32_t year;
 } publish_t;
-    
+
 typedef struct {
-    int null_;
+  int null_;
 } nulldata_t;
 
 typedef struct {
-    char *title;
-    int   n_authors;
-    char **authors;
-    int   n_chapters;
-    chapter_t *chapters_;
-    publish_t *publish;
-    nulldata_t *nulldata;
-    int   n_magic1;
-    uint32_t *magic_1;
-    char *description;
-    int   acquire_method;
-    union {
-	char *buy;
-	char *donation;
-    } acquire;
+  char *from;
+  int with_recipe;
+  union {
+    char *recipe_addr;
+  } u;
+} buy_t;
+
+typedef struct {
+  char *title;
+  int n_authors;
+  char **authors;
+  int n_chapters;
+  chapter_t **chapters_;
+  publish_t *publish;
+  nulldata_t *nulldata;
+  int n_magic1;
+  uint32_t *magic_1;
+  char *description;
+  int acquire_method;
+  union {
+    buy_t *buy;
+    char *donation;
+  } acquire;
 } book_t;
 
 #endif
diff --git a/examples/book/test.c b/examples/book/test.c
index 357f918..7e6272f 100644
--- a/examples/book/test.c
+++ b/examples/book/test.c
@@ -20,7 +20,7 @@ int encode() {
     uint32_t magic1[2] = {
 	1101,1012
     };
-    chapter_t chapters[3] = {
+    chapter_t chapters_[3] = {
 	{.caption ="Chapter1",
 	 .start =1,
 	 .end=99},
@@ -31,10 +31,20 @@ int encode() {
 	 .start = 151,
 	 .end=199}
     };
+    chapter_t* chapters[3] = {
+	&chapters_[0], &chapters_[1], &chapters_[2]
+    };
     publish_t publish = {
 	.isbn = 335677,
 	.year =2001
     };
+    buy_t buy = {
+	.from = "Xinghua Book store",
+	.with_recipe = Buy_u_recipeAddr,
+	.u = {
+	    .recipe_addr = "Xinghua Street"
+	}
+    };
     struct capn_segment *cs;
     struct Book b;
     Book_ptr p;
@@ -50,7 +60,7 @@ int encode() {
     book.magic_1 = &magic1[0];
     book.description = NULL;
     book.acquire_method = Book_acquire_buy;
-    book.acquire.buy = "bought from Xinhua book store";
+    book.acquire.buy = &buy;
 
     capn_init_malloc(&c);
     cs = capn_root(&c).seg;
@@ -87,10 +97,10 @@ int decode() {
     
     printf("chapters(%d):\n", book->n_chapters);
     for(i = 0; i < book->n_chapters; i ++) {
-	printf("\tcaption: %s\n", book->chapters_[i].caption);
+	printf("\tcaption: %s\n", book->chapters_[i]->caption);
 	printf("\tfrom %d to %d\n",
-	       book->chapters_[i].start,
-	       book->chapters_[i].end);
+	       book->chapters_[i]->start,
+	       book->chapters_[i]->end);
     }
 
     printf("ISBN: %lu year: %u\n",
@@ -103,12 +113,19 @@ int decode() {
     }
 
     if (book->acquire_method == Book_acquire_buy) {
-	printf("%s\n", book->acquire.buy);
+	printf("buy from %s\n", book->acquire.buy->from);
+	if (book->acquire.buy->with_recipe == Buy_u_recipeAddr) {
+	    printf("recipe address %s\n",
+		   book->acquire.buy->u.recipe_addr);
+	}
     }
     else {
 	printf("%s\n", book->acquire.donation);
     }
     
+    free_Book_ptr(&book);
+    capn_free(&c);
+    
     return 0;
 }
 
diff --git a/xmake.lua b/xmake.lua
index 5c5bbf4..e0cda0f 100644
--- a/xmake.lua
+++ b/xmake.lua
@@ -49,10 +49,12 @@ target("book")
 	add_files("examples/book/*.c")
 	add_includedirs("compiler","lib","examples/book")
 	add_deps("CapnC_Runtime", "capnpc-c")
+	add_cflags("-fsanitize=address")
+	add_ldflags("-fsanitize=address")
 
 xpack("capnpc-c")
 	set_formats("targz")
 	set_title("c-capnproto")
 	set_licensefile("COPYING")
 	add_targets("capnpc-c", "CapnC_Runtime")
-	
\ No newline at end of file
+