also bind return code for dbuse?

Author: andyundso

ext/tiny_tds/client.c

@@ -944,8 +944,8 @@ static void *
 dbuse_without_gvl(void *ptr)
 {
   struct dbuse_args *args = (struct dbuse_args *)ptr;
-  dbuse(args->dbproc, args->name);
-  return NULL;
+  RETCODE rc = dbuse(args->dbproc, args->name);
+  return (void *)(intptr_t)rc;
 }
 
 static VALUE rb_tinytds_connect(VALUE self)
@@ -1060,14 +1060,18 @@ static VALUE rb_tinytds_connect(VALUE self)
       use_args.dbproc = cwrap->client;
       use_args.name = StringValueCStr(database);
 
-      // in case of any errors, the tinytds_err_handler will be called
-      // so we do not have to check the return code here
-      rb_thread_call_without_gvl(
-        dbuse_without_gvl,
-        &use_args,
-        NULL,
-        NULL
-      );
+      nogvl_setup(cwrap->client);
+      RETCODE retcode = (RETCODE)(intptr_t)rb_thread_call_without_gvl(
+                          dbuse_without_gvl,
+                          &use_args,
+                          NULL,
+                          NULL
+                        );
+      nogvl_cleanup(cwrap->client);
+
+      if (retcode == FAIL) {
+        rb_raise(cTinyTdsError, "Unable to change to database %s.", use_args.name);
+      }
     }
 
     transposed_encoding = rb_funcall(cTinyTdsClient, intern_transpose_iconv_encoding, 1, charset);