check_format_string

Checks if calling @get with format_string on this would be valid from a type-compatibility standpoint.

format_string is assumed to be a valid format string (from a syntactic standpoint).

If copy_only is true then this function additionally checks that it would be safe to call g_variant_unref on this immediately after the call to @get without invalidating the result. This is only possible if deep copies are made ( ie: there are no pointers to the data inside of the soon-to-be-freed Variant instance). If this check fails then a critical is printed and false is returned.

This function is meant to be used by functions that wish to provide varargs accessors to Variant values of uncertain values (eg: lookup or get_item_attribute).

Parameters:

this	a Variant
format_string	a valid Variant format string
copy_only	true to ensure the format string makes deep copies

Returns:

true if format_string is safe to use