Function

GLibdatalist_id_replace_data

Declaration

gboolean
g_datalist_id_replace_data (
  GData** datalist,
  GQuark key_id,
  gpointer oldval,
  gpointer newval,
  GDestroyNotify destroy,
  GDestroyNotify* old_destroy
)

Description

Compares the member that is associated with key_id in datalist to oldval, and if they are the same, replace oldval with newval.

This is like a typical atomic compare-and-exchange operation, for a member of datalist.

If the previous value was replaced then ownership of the old value (oldval) is passed to the caller, including the registered destroy notify for it (passed out in old_destroy). Its up to the caller to free this as he wishes, which may or may not include using old_destroy as sometimes replacement should not destroy the object in the normal way.

Available since:

2.34

Parameters

`datalist`	`GData`
	Location of a datalist.
	The data is owned by the caller of the function.
`key_id`	`GQuark`
	The `GQuark` identifying a data element.
`oldval`	`gpointer`
	The old value to compare against.
`newval`	`gpointer`
	The new value to replace it with.
`destroy`	`GDestroyNotify`
	Destroy notify for the new value.
`old_destroy`	`GDestroyNotify`
	Destroy notify for the existing value.
	The argument will be set by the function.
	The argument can be `NULL`.
	The data is owned by the caller of the function.

Return value

Returns:	`gboolean`
	`TRUE` if the existing value for `key_id` was replaced by `newval`, `FALSE` otherwise.