Improved portability to older SQLite3 versions

Author: mmottl

CHANGES.md

@@ -1,7 +1,9 @@
-### ?.?.? (????-??-??)
+### 5.0.1 (2019-12-01)
 
   * Added missing :with-test declaration in Dune project file.
 
+  * Improved portability to older SQLite3 versions.
+
 
 ### 5.0.0 (2019-12-01)
 

src/sqlite3_stubs.c

@@ -540,10 +540,10 @@ CAMLprim value caml_sqlite3_open(
     size_t db_wrap_size = sizeof(db_wrap);
     db_wrap *dbw = caml_stat_alloc(db_wrap_size);
     value v_res;
+#if (OCAML_VERSION_MAJOR >= 4 && OCAML_VERSION_MINOR >= 8 && SQLITE_DBSTATUS_CACHE_USED)
     int mem, hiwtr;
     int rc = sqlite3_db_status(db, SQLITE_DBSTATUS_CACHE_USED, &mem, &hiwtr, 0);
     mem = db_wrap_size + (rc ? 8192 : mem);
-#if (OCAML_VERSION_MAJOR >= 4 && OCAML_VERSION_MINOR >= 8)
     v_res = caml_alloc_custom_mem(&db_wrap_ops, sizeof(db_wrap *), mem);
 #else
     v_res = caml_alloc_custom(&db_wrap_ops, sizeof(db_wrap *), 1, 1000);
@@ -906,7 +906,7 @@ static inline value prepare_it(
     if (rc != SQLITE_OK) raise_sqlite3_current(dbw->db, loc);
     raise_sqlite3_Error("No code compiled from %s", sql);
   } else {
-#if (OCAML_VERSION_MAJOR >= 4 && OCAML_VERSION_MINOR >= 8)
+#if (OCAML_VERSION_MAJOR >= 4 && OCAML_VERSION_MINOR >= 8 && SQLITE_STMTSTATUS_MEMUSED)
     size_t mem =
       sizeof(stmt_wrap) + sql_len + 1 +
       sqlite3_stmt_status(stmtw->stmt, SQLITE_STMTSTATUS_MEMUSED, 0);