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The GQueue structure and its associated functions provide a standard queue data structure. Internally, GQueue uses the same data structure as GList to store elements with the same complexity over insertion/deletion (O(1)) and access/search (O(n)) operations.
The data contained in each element can be either integer values, by using one of the Type Conversion Macros, or simply pointers to any type of data.
As with all other GLib data structures, GQueue is not thread-safe. For a thread-safe queue, use GAsyncQueue.
To create a new GQueue, use g_queue_new().
To initialize a statically-allocated GQueue, use G_QUEUE_INIT or
g_queue_init().
To add elements, use g_queue_push_head(), g_queue_push_head_link(),
g_queue_push_tail() and g_queue_push_tail_link().
To remove elements, use g_queue_pop_head() and g_queue_pop_tail().
To free the entire queue, use g_queue_free().
void
g_queue_free (GQueue *queue);
Frees the memory allocated for the GQueue. Only call this function
if queue
was created with g_queue_new(). If queue elements contain
dynamically-allocated memory, they should be freed first.
If queue elements contain dynamically-allocated memory, you should
either use g_queue_free_full() or free them manually first.
void g_queue_free_full (GQueue *queue,GDestroyNotify free_func);
Convenience method, which frees all the memory used by a GQueue, and calls the specified destroy function on every element's data.
free_func
should not modify the queue (eg, by removing the freed
element from it).
queue |
a pointer to a GQueue |
|
free_func |
the function to be called to free each element's data |
Since: 2.32
void
g_queue_init (GQueue *queue);
A statically-allocated GQueue must be initialized with this function
before it can be used. Alternatively you can initialize it with
G_QUEUE_INIT. It is not necessary to initialize queues created with
g_queue_new().
Since: 2.14
void
g_queue_clear (GQueue *queue);
Removes all the elements in queue
. If queue elements contain
dynamically-allocated memory, they should be freed first.
Since: 2.14
void g_queue_clear_full (GQueue *queue,GDestroyNotify free_func);
Convenience method, which frees all the memory used by a GQueue,
and calls the provided free_func
on each item in the GQueue.
queue |
a pointer to a GQueue |
|
free_func |
the function to be called to free memory allocated. |
[nullable] |
Since: 2.60
guint
g_queue_get_length (GQueue *queue);
Returns the number of items in queue
.
Since: 2.4
void
g_queue_reverse (GQueue *queue);
Reverses the order of the items in queue
.
Since: 2.4
GQueue *
g_queue_copy (GQueue *queue);
Copies a queue
. Note that is a shallow copy. If the elements in the
queue consist of pointers to data, the pointers are copied, but the
actual data is not.
Since: 2.4
void g_queue_foreach (GQueue *queue,GFunc func,gpointer user_data);
Calls func
for each element in the queue passing user_data
to the
function.
It is safe for func
to remove the element from queue
, but it must
not modify any part of the queue after that element.
queue |
a GQueue |
|
func |
the function to call for each element's data |
|
user_data |
user data to pass to |
Since: 2.4
GList * g_queue_find (GQueue *queue,gconstpointer data);
Finds the first link in queue
which contains data
.
Since: 2.4
GList * g_queue_find_custom (GQueue *queue,gconstpointer data,GCompareFunc func);
Finds an element in a GQueue, using a supplied function to find the desired element. It iterates over the queue, calling the given function which should return 0 when the desired element is found. The function takes two gconstpointer arguments, the GQueue element's data as the first argument and the given user data as the second argument.
queue |
a GQueue |
|
data |
user data passed to |
|
func |
a GCompareFunc to call for each element. It should return 0 when the desired element is found |
Since: 2.4
void g_queue_sort (GQueue *queue,GCompareDataFunc compare_func,gpointer user_data);
Sorts queue
using compare_func
.
queue |
a GQueue |
|
compare_func |
the GCompareDataFunc used to sort |
|
user_data |
user data passed to |
Since: 2.4
void g_queue_push_head (GQueue *queue,gpointer data);
Adds a new element at the head of the queue.
void g_queue_push_tail (GQueue *queue,gpointer data);
Adds a new element at the tail of the queue.
void g_queue_push_nth (GQueue *queue,gpointer data,gint n);
Inserts a new element into queue
at the given position.
queue |
a GQueue |
|
data |
the data for the new element |
|
n |
the position to insert the new element. If |
Since: 2.4
gpointer
g_queue_pop_head (GQueue *queue);
Removes the first element of the queue and returns its data.
gpointer
g_queue_pop_tail (GQueue *queue);
Removes the last element of the queue and returns its data.
gpointer g_queue_pop_nth (GQueue *queue,guint n);
Removes the n
'th element of queue
and returns its data.
Since: 2.4
gpointer
g_queue_peek_head (GQueue *queue);
Returns the first element of the queue.
gpointer
g_queue_peek_tail (GQueue *queue);
Returns the last element of the queue.
gpointer g_queue_peek_nth (GQueue *queue,guint n);
Returns the n
'th element of queue
.
Since: 2.4
gint g_queue_index (GQueue *queue,gconstpointer data);
Returns the position of the first element in queue
which contains data
.
the position of the first element in queue
which
contains data
, or -1 if no element in queue
contains data
Since: 2.4
gboolean g_queue_remove (GQueue *queue,gconstpointer data);
Removes the first element in queue
that contains data
.
Since: 2.4
guint g_queue_remove_all (GQueue *queue,gconstpointer data);
Remove all elements whose data equals data
from queue
.
Since: 2.4
void g_queue_insert_before (GQueue *queue,GList *sibling,gpointer data);
Inserts data
into queue
before sibling
.
sibling
must be part of queue
. Since GLib 2.44 a NULL sibling pushes the
data at the tail of the queue.
Since: 2.4
void g_queue_insert_before_link (GQueue *queue,GList *sibling,GList *link_);
Inserts link_
into queue
before sibling
.
sibling
must be part of queue
.
Since: 2.62
void g_queue_insert_after (GQueue *queue,GList *sibling,gpointer data);
Inserts data
into queue
after sibling
.
sibling
must be part of queue
. Since GLib 2.44 a NULL sibling pushes the
data at the head of the queue.
Since: 2.4
void g_queue_insert_after_link (GQueue *queue,GList *sibling,GList *link_);
Inserts link_
into queue
after sibling
.
sibling
must be part of queue
.
Since: 2.62
void g_queue_insert_sorted (GQueue *queue,gpointer data,GCompareDataFunc func,gpointer user_data);
Inserts data
into queue
using func
to determine the new position.
queue |
a GQueue |
|
data |
the data to insert |
|
func |
the GCompareDataFunc used to compare elements in the queue. It is
called with two elements of the |
|
user_data |
user data passed to |
Since: 2.4
void g_queue_push_head_link (GQueue *queue,GList *link_);
Adds a new element at the head of the queue.
void g_queue_push_tail_link (GQueue *queue,GList *link_);
Adds a new element at the tail of the queue.
void g_queue_push_nth_link (GQueue *queue,gint n,GList *link_);
Inserts link
into queue
at the given position.
queue |
a GQueue |
|
n |
the position to insert the link. If this is negative or larger than
the number of elements in |
|
link_ |
the link to add to |
Since: 2.4
GList *
g_queue_pop_head_link (GQueue *queue);
Removes and returns the first element of the queue.
GList *
g_queue_pop_tail_link (GQueue *queue);
Removes and returns the last element of the queue.
GList * g_queue_pop_nth_link (GQueue *queue,guint n);
Removes and returns the link at the given position.
Since: 2.4
GList *
g_queue_peek_head_link (GQueue *queue);
Returns the first link in queue
.
Since: 2.4
GList *
g_queue_peek_tail_link (GQueue *queue);
Returns the last link in queue
.
Since: 2.4
GList * g_queue_peek_nth_link (GQueue *queue,guint n);
Returns the link at the given position
Since: 2.4
gint g_queue_link_index (GQueue *queue,GList *link_);
Returns the position of link_
in queue
.
Since: 2.4
void g_queue_unlink (GQueue *queue,GList *link_);
Unlinks link_
so that it will no longer be part of queue
.
The link is not freed.
link_
must be part of queue
.
Since: 2.4
struct GQueue {
GList *head;
GList *tail;
guint length;
};
Contains the public fields of a Queue.
#define G_QUEUE_INIT { NULL, NULL, 0 }
A statically-allocated GQueue must be initialized with this
macro before it can be used. This macro can be used to initialize
a variable, but it cannot be assigned to a variable. In that case
you have to use g_queue_init().
1 |
GQueue my_queue = G_QUEUE_INIT; |
Since: 2.14