Description
The GSList structure and its associated functions provide a
standard singly-linked list data structure.
Each element in the list contains a piece of data, together with a
pointer which links to the next element in the list. Using this
pointer it is possible to move through the list in one direction
only (unlike the double-linked lists,
which allow movement in both directions).
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.
List elements are allocated from the slice allocator,
which is more efficient than allocating elements individually.
Note that most of the GSList functions expect to be passed a
pointer to the first element in the list. The functions which insert
elements return the new start of the list, which may have changed.
There is no function to create a GSList. NULL is considered to be
the empty list so you simply set a GSList* to NULL.
To add elements, use g_slist_append(), g_slist_prepend(),
g_slist_insert() and g_slist_insert_sorted().
To remove elements, use g_slist_remove().
To find elements in the list use g_slist_last(), g_slist_next(),
g_slist_nth(), g_slist_nth_data(), g_slist_find() and
g_slist_find_custom().
To find the index of an element use g_slist_position() and
g_slist_index().
To call a function for each element in the list use
g_slist_foreach().
To free the entire list, use g_slist_free().
Functions
g_slist_append ()
GSList *
g_slist_append (GSList *list,
gpointer data);
Adds a new element on to the end of the list.
The return value is the new start of the list, which may
have changed, so make sure you store the new value.
Note that g_slist_append() has to traverse the entire list
to find the end, which is inefficient when adding multiple
elements. A common idiom to avoid the inefficiency is to prepend
the elements and reverse the list when all elements have been added.
Returns
the new start of the GSList
g_slist_prepend ()
GSList *
g_slist_prepend (GSList *list,
gpointer data);
Adds a new element on to the start of the list.
The return value is the new start of the list, which
may have changed, so make sure you store the new value.
Returns
the new start of the GSList
g_slist_insert ()
GSList *
g_slist_insert (GSList *list,
gpointer data,
gint position);
Inserts a new element into the list at the given position.
Returns
the new start of the GSList
g_slist_insert_before ()
GSList *
g_slist_insert_before (GSList *slist,
GSList *sibling,
gpointer data);
Inserts a node before sibling
containing data
.
Returns
the new head of the list.
g_slist_insert_sorted ()
GSList *
g_slist_insert_sorted (GSList *list,
gpointer data,
GCompareFunc func);
Inserts a new element into the list, using the given
comparison function to determine its position.
Returns
the new start of the GSList
g_slist_remove ()
GSList *
g_slist_remove (GSList *list,
gconstpointer data);
Removes an element from a GSList.
If two elements contain the same data, only the first is removed.
If none of the elements contain the data, the GSList is unchanged.
Returns
the new start of the GSList
g_slist_remove_link ()
GSList *
g_slist_remove_link (GSList *list,
GSList *link_);
Removes an element from a GSList, without
freeing the element. The removed element's next
link is set to NULL, so that it becomes a
self-contained list with one element.
Removing arbitrary nodes from a singly-linked list
requires time that is proportional to the length of the list
(ie. O(n)). If you find yourself using g_slist_remove_link()
frequently, you should consider a different data structure,
such as the doubly-linked GList.
Returns
the new start of the GSList, without the element
g_slist_delete_link ()
GSList *
g_slist_delete_link (GSList *list,
GSList *link_);
Removes the node link_ from the list and frees it.
Compare this to g_slist_remove_link() which removes the node
without freeing it.
Removing arbitrary nodes from a singly-linked list requires time
that is proportional to the length of the list (ie. O(n)). If you
find yourself using g_slist_delete_link() frequently, you should
consider a different data structure, such as the doubly-linked
GList.
Returns
the new head of list
g_slist_remove_all ()
GSList *
g_slist_remove_all (GSList *list,
gconstpointer data);
Removes all list nodes with data equal to data
.
Returns the new head of the list. Contrast with
g_slist_remove() which removes only the first node
matching the given data.
g_slist_free ()
void
g_slist_free (GSList *list);
Frees all of the memory used by a GSList.
The freed elements are returned to the slice allocator.
If list elements contain dynamically-allocated memory,
you should either use g_slist_free_full() or free them manually
first.
It can be combined with g_steal_pointer() to ensure the list head pointer
is not left dangling:
g_slist_free_full ()
void
g_slist_free_full (GSList *list,
GDestroyNotify free_func);
Convenience method, which frees all the memory used by a GSList, and
calls the specified destroy function on every element's data.
free_func
must not modify the list (eg, by removing the freed
element from it).
It can be combined with g_steal_pointer() to ensure the list head pointer
is not left dangling — this also has the nice property that the head pointer
is cleared before any of the list elements are freed, to prevent double frees
from free_func
:
Since: 2.28
g_clear_slist ()
void
g_clear_slist (GSList **slist_ptr,
GDestroyNotify destroy);
Clears a pointer to a GSList, freeing it and, optionally, freeing its elements using destroy
.
slist_ptr
must be a valid pointer. If slist_ptr
points to a null GSList, this does nothing.
[skip]
Since: 2.64
g_slist_length ()
guint
g_slist_length (GSList *list);
Gets the number of elements in a GSList.
This function iterates over the whole list to
count its elements. To check whether the list is non-empty, it is faster to
check list
against NULL.
Returns
the number of elements in the GSList
g_slist_copy ()
GSList *
g_slist_copy (GSList *list);
Copies a GSList.
Note that this is a "shallow" copy. If the list elements
consist of pointers to data, the pointers are copied but
the actual data isn't. See g_slist_copy_deep() if you need
to copy the data as well.
g_slist_copy_deep ()
GSList *
g_slist_copy_deep (GSList *list,
GCopyFunc func,
gpointer user_data);
Makes a full (deep) copy of a GSList.
In contrast with g_slist_copy(), this function uses func
to make a copy of
each list element, in addition to copying the list container itself.
func
, as a GCopyFunc, takes two arguments, the data to be copied
and a user_data
pointer. On common processor architectures, it's safe to
pass NULL as user_data
if the copy function takes only one argument. You
may get compiler warnings from this though if compiling with GCC’s
-Wcast-function-type warning.
For instance, if list
holds a list of GObjects, you can do:
And, to entirely free the new list, you could do:
Since: 2.34
g_slist_insert_sorted_with_data ()
GSList *
g_slist_insert_sorted_with_data (GSList *list,
gpointer data,
GCompareDataFunc func,
gpointer user_data);
Inserts a new element into the list, using the given
comparison function to determine its position.
Returns
the new start of the GSList
Since: 2.10
g_slist_sort ()
GSList *
g_slist_sort (GSList *list,
GCompareFunc compare_func);
Sorts a GSList using the given comparison function. The algorithm
used is a stable sort.
Returns
the start of the sorted GSList
g_slist_concat ()
GSList *
g_slist_concat (GSList *list1,
GSList *list2);
Adds the second GSList onto the end of the first GSList.
Note that the elements of the second GSList are not copied.
They are used directly.
Returns
the start of the new GSList
g_slist_foreach ()
void
g_slist_foreach (GSList *list,
GFunc func,
gpointer user_data);
Calls a function for each element of a GSList.
It is safe for func
to remove the element from list
, but it must
not modify any part of the list after that element.
g_slist_last ()
GSList *
g_slist_last (GSList *list);
Gets the last element in a GSList.
This function iterates over the whole list.
g_slist_next()
#define g_slist_next(slist)
A convenience macro to get the next element in a GSList.
Note that it is considered perfectly acceptable to access
slist->next
directly.
Returns
the next element, or NULL if there are no more elements.
g_slist_nth ()
GSList *
g_slist_nth (GSList *list,
guint n);
Gets the element at the given position in a GSList.
Returns
the element, or NULL if the position is off
the end of the GSList
g_slist_nth_data ()
gpointer
g_slist_nth_data (GSList *list,
guint n);
Gets the data of the element at the given position.
Returns
the element's data, or NULL if the position
is off the end of the GSList
g_slist_find_custom ()
GSList *
g_slist_find_custom (GSList *list,
gconstpointer data,
GCompareFunc func);
Finds an element in a GSList, using a supplied function to
find the desired element. It iterates over the list, calling
the given function which should return 0 when the desired
element is found. The function takes two gconstpointer arguments,
the GSList element's data as the first argument and the
given user data.
Returns
the found GSList element, or NULL if it is not found
g_slist_position ()
gint
g_slist_position (GSList *list,
GSList *llink);
Gets the position of the given element
in the GSList (starting from 0).
Returns
the position of the element in the GSList,
or -1 if the element is not found
g_slist_index ()
gint
g_slist_index (GSList *list,
gconstpointer data);
Gets the position of the element containing
the given data (starting from 0).
Returns
the index of the element containing the data,
or -1 if the data is not found