diff --git a/src/legacy.c b/src/legacy.c
index 4b77b81..a4437cb 100644
--- a/src/legacy.c
+++ b/src/legacy.c
@@ -41,6 +41,7 @@ void sqlite3_exec_(
   const int ret_code = sqlite3_exec(db, zSql, xCallback, pArg, &pzErrMsg);
 
   free(zSql);
+
   int *result = malloc(3*8);
   result[0] = ret_code;
   result[1] = 0;
@@ -49,8 +50,10 @@ void sqlite3_exec_(
   result[4] = strlen(pzErrMsg);
   result[5] = 0;
 
+  // errmsg should be managed by user
+  add_object_to_release((void *) pzErrMsg);
   add_object_to_release((void *) result);
-  set_result_ptr((char *)result);
+  set_result_ptr((void *) result);
 }
 
 int sqlite3_exec(
diff --git a/src/main.c b/src/main.c
index f9490e1..18e568a 100644
--- a/src/main.c
+++ b/src/main.c
@@ -2452,8 +2452,8 @@ int sqlite3TempInMemory(const sqlite3 *db){
 void sqlite3_errmsg_(sqlite3 *db) __EXPORT_NAME(sqlite3_errmsg) {
   const char *result = sqlite3_errmsg(db);
 
-  add_object_to_release((void *) result);
-  set_result_ptr((char *)result);
+  // result is managed by SQLite itself
+  set_result_ptr((void *) result);
   set_result_size(strlen(result));
 }
 
@@ -3460,7 +3460,7 @@ void sqlite3_open_v2_(
   result[2] = (int)ppDb;
 
   add_object_to_release((void *) result);
-  set_result_ptr((char *)result);
+  set_result_ptr((void *)result);
 }
 
 int sqlite3_open_v2(
diff --git a/src/prepare.c b/src/prepare.c
index 0100ffc..a42a2d1 100644
--- a/src/prepare.c
+++ b/src/prepare.c
@@ -788,11 +788,11 @@ void sqlite3_prepare_v2_(
   const char *zSql,         /* UTF-8 encoded SQL statement. */
   int nBytes                /* Length of zSql in bytes. */
 ) __EXPORT_NAME(sqlite3_prepare_v2) {
-  sqlite3_stmt *ppStmt;
-  const char *pzTail;
+  sqlite3_stmt *ppStmt = NULL;
+  const char *pzTail = NULL;
 
   const int ret_code = sqlite3_prepare_v2(db, zSql, nBytes, &ppStmt, &pzTail);
-  free((void *)zSql);
+  free((void *) zSql);
 
   int *result = (int *)malloc(3*8);
   result[0] = ret_code;
@@ -800,7 +800,8 @@ void sqlite3_prepare_v2_(
   result[4] = (int)pzTail;
   result[5] = strlen(pzTail);
 
-  set_result_ptr((char *)result);
+  add_object_to_release((void *) result);
+  set_result_ptr((void *) result);
 }
 
 int sqlite3_prepare_v2(
diff --git a/src/sqlite3.h b/src/sqlite3.h
index 80780cb..7b230c4 100644
--- a/src/sqlite3.h
+++ b/src/sqlite3.h
@@ -37,9 +37,6 @@
 #define __EXPORT_NAME(name) \
     __attribute__((export_name(#name)))
 
-void set_result_ptr(const char *ptr);
-void set_result_size(int size);
-
 /*
 ** Make sure we can call this stuff from C++.
 */
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index f6cc172..07d7b43 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -4911,7 +4911,7 @@ const char **sqlite3CompileOptions(int *pnOpt);
 #ifndef __sqlite_unmodified_upstram
 void add_object_to_release(void *object);
 
-void set_result_ptr(const char *ptr);
+void set_result_ptr(void *ptr);
 void set_result_size(int size);
 #endif
 
diff --git a/src/vdbeapi.c b/src/vdbeapi.c
index 0240038..5879664 100644
--- a/src/vdbeapi.c
+++ b/src/vdbeapi.c
@@ -1113,7 +1113,8 @@ void sqlite3_column_blob_(sqlite3_stmt *pStmt, int i) __EXPORT_NAME(sqlite3_colu
    const char *blob = sqlite3_column_blob(pStmt, i);
    int blob_len = sqlite3_column_bytes(pStmt, i);
 
-   set_result_ptr((char *)blob);
+   // blob is managed by SQLite itself
+   set_result_ptr((void *)blob);
    set_result_size(blob_len);
 }
 
@@ -1157,7 +1158,8 @@ void sqlite3_column_text_(sqlite3_stmt *pStmt, int i) __EXPORT_NAME(sqlite3_colu
   const unsigned char *text = sqlite3_column_text(pStmt, i);
   const unsigned int text_len = sqlite3_column_bytes(pStmt, i);
 
-  set_result_ptr((char *)text);
+  // test is managed by SQLite itself
+  set_result_ptr((void *) text);
   set_result_size(text_len);
 }
 
@@ -1256,8 +1258,8 @@ static const void *columnName(
 void sqlite3_column_name_(sqlite3_stmt *pStmt, int N) __EXPORT_NAME(sqlite3_column_name) {
   const char *result = sqlite3_column_name(pStmt, N);
 
-  add_object_to_release((void *) result);
-  set_result_ptr((char *)result);
+  // result is managed by SQLite itself
+  set_result_ptr((void *)result);
   set_result_size(strlen(result));
 }
 
diff --git a/src/wrapper.c b/src/wrapper.c
index bdd7eaa..0a2a787 100644
--- a/src/wrapper.c
+++ b/src/wrapper.c
@@ -3,7 +3,7 @@
 
 #include <stdlib.h>
 
-const char *RESULT_PTR;
+void *RESULT_PTR;
 int RESULT_SIZE;
 
 cvector_vector_type(void *) OBJECTS_TO_RELEASE;
@@ -27,7 +27,7 @@ void add_object_to_release(void *object) {
   cvector_push_back(OBJECTS_TO_RELEASE, object);
 }
 
-void set_result_ptr(const char *ptr) {
+void set_result_ptr(void *ptr) {
   RESULT_PTR = ptr;
 }
 
@@ -39,7 +39,7 @@ int get_result_size(void) {
   return RESULT_SIZE;
 }
 
-const char *get_result_ptr() {
+void *get_result_ptr() {
   return RESULT_PTR;
 }