/**
* g_error_matches:
- * @error: a #GError or %NULL
+ * @error: (allow-none): a #GError or %NULL
* @domain: an error domain
* @code: an error code
*
/**
* g_set_error:
- * @err: a return location for a #GError, or %NULL
+ * @err: (allow-none): a return location for a #GError, or %NULL
* @domain: error domain
* @code: error code
* @format: printf()-style format
/**
* g_set_error_literal:
- * @err: a return location for a #GError, or %NULL
+ * @err: (allow-none): a return location for a #GError, or %NULL
* @domain: error domain
* @code: error code
* @message: error message
/**
* g_prefix_error:
- * @err: a return location for a #GError, or %NULL
+ * @err: (allow-none): a return location for a #GError, or %NULL
* @format: printf()-style format string
* @...: arguments to @format
*