Checks if calling g_variant_get() with format_string on value 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 value immediately after
the call to g_variant_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 GVariant instance). If this
check fails then a g_critical() is printed and FALSE is returned.
This function is meant to be used by functions that wish to provide
Since 2.34
Checks if calling g_variant_get() with format_string on value 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 value immediately after the call to g_variant_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 GVariant instance). If this check fails then a g_critical() is printed and FALSE is returned. This function is meant to be used by functions that wish to provide Since 2.34