Function

GLibdatalist_id_replace_data

since: 2.34

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 they wish, 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

This function is not directly available to language bindings.

Parameters

datalist

Type: GData

Location of a datalist.

The data is owned by the caller of the function.
key_id

Type: GQuark

The GQuark identifying a data element.

oldval

Type: gpointer

The old value to compare against.

The argument can be NULL.
The data is owned by the caller of the function.
newval

Type: gpointer

The new value to replace it with.

The argument can be NULL.
The data is owned by the caller of the function.
destroy

Type: GDestroyNotify

Destroy notify for the new value.

The argument can be NULL.
old_destroy

Type: GDestroyNotify

Destroy notify for the existing value.

The argument will be set by the function.
The argument can be NULL.
The returned data is owned by the function.

Return value

Type: gboolean

TRUE if the existing value for key_id was replaced by newval, FALSE otherwise.