GLib Reference Manual | |||
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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 Doubly-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 in blocks using a GListAllocator, 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().
struct GSList { gpointer data; GSList *next; }; |
The GSList struct is used for each element in the singly-linked list. The data field holds the element's data, which can be a pointer to any kind of data, or any integer value using the Type Conversion Macros. The next field contains the link to the next element in the list.
GSList* g_slist_alloc (void); |
Allocates space for one GSList element. It is called by the g_slist_append(), g_slist_prepend(), g_slist_insert() and g_slist_insert_sorted() functions and so is rarely used on its own.
Returns : | a pointer to the newly-allocated GSList element. |
GSList* g_slist_append (GSList *list, gpointer data); |
Adds a new element on to the end of the list.
Note: The return value is the new start of the list, which may have changed, so make sure you store the new value.
/* Notice that these are initialized to the empty list. */ GSList *list = NULL, *number_list = NULL; /* This is a list of strings. */ list = g_slist_append (list, "first"); list = g_slist_append (list, "second"); /* This is a list of integers. */ number_list = g_slist_append (number_list, GINT_TO_POINTER (27)); number_list = g_slist_append (number_list, GINT_TO_POINTER (14)); |
GSList* g_slist_prepend (GSList *list, gpointer data); |
Adds a new element on to the start of the list.
Note: The return value is the new start of the list, which may have changed, so make sure you store the new value.
/* Notice that it is initialized to the empty list. */ GSList *list = NULL; list = g_slist_prepend (list, "last"); list = g_slist_prepend (list, "first"); |
GSList* g_slist_insert (GSList *list, gpointer data, gint position); |
Inserts a new element into the list at the given position.
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.
GSList* g_slist_remove (GSList *list, gpointer 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.
GSList* g_slist_remove_link (GSList *list, GSList *llink); |
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.
void g_slist_free (GSList *list); |
Frees all of the memory used by a GSList. The freed elements are added to the GListAllocator free list.
list : | a GSList. |
void g_slist_free_1 (GSList *list); |
Frees one GSList element. It is usually used after g_slist_remove_link().
list : | a GSList element. |
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.
list : | a GSList. |
Returns : | a copy of list. |
GSList* g_slist_sort (GSList *list, GCompareFunc compare_func); |
Sorts a GSList using the given comparison function.
list : | a GSList. |
compare_func : | the comparison function used to sort the GSList. This function is passed 2 elements of the GSList and should return 0 if they are equal, a negative value if the first element comes before the second, or a positive value if the first element comes after the second. |
Returns : | the start of the sorted GList. |
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.
void g_slist_foreach (GSList *list, GFunc func, gpointer user_data); |
Calls a function for each element of a GSList.
list : | a GSList. |
func : | the function to call with each element's data. |
user_data : | user data to pass to the function. |
#define g_slist_next(slist) |
A convenience macro to gets the next element in a GSList.
slist : | an element in a GSList. |
Returns : | the next element, or NULL if there are no more elements. |
GSList* g_slist_nth (GSList *list, guint n); |
Gets the element at the given position in a GSList.
gpointer g_slist_nth_data (GSList *list, guint n); |
Gets the data of the element at the given position.
GSList* g_slist_find (GSList *list, gpointer data); |
Finds the element in a GSList which contains the given data.
GSList* g_slist_find_custom (GSList *list, gpointer 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 and the given user data.
gint g_slist_position (GSList *list, GSList *llink); |
Gets the position of the given element in the GSList (starting from 0).
gint g_slist_index (GSList *list, gpointer data); |
Gets the position of the element containing the given data (starting from 0).
list : | a GSList. |
data : | the data to find. |
Returns : | the index of the element containing the data, or -1 if the data is not found. |
void g_slist_push_allocator (GAllocator *allocator); |
Sets the allocator to use to allocate GSList elements. Use g_slist_pop_allocator() to restore the previous allocator.
allocator : | the GAllocator to use when allocating GSList elements. |
void g_slist_pop_allocator (void); |
Restores the previous GAllocator, used when allocating GSList elements.