GSList

GSList is GLib's implementation of a generic singly linked list. It provides a simple, dynamically allocated chain of nodes where each node holds a pointer to data (gpointer) and a pointer to the next node. Because the data field is a void pointer, GSList can store pointers to any type, making it a flexible container for GTK and GLib-based projects.

Structure and usage: A GSList is a singly linked list, so insertion and removal at the head is typically constant time, while operations at the tail or in the middle may require traversal. The core API offers a variety of constructors, mutators, and accessors. Common operations include g_slist_prepend to add an element at the front, g_slist_append to add to the end, and g_slist_insert to place an element at a specified position. Other utilities cover removal (g_slist_remove, g_slist_remove_all), access (g_slist_nth, g_slist_nth_data, g_slist_last), queries (g_slist_length), and common transformations such as g_slist_reverse, g_slist_concat, and g_slist_sort (with an optional variant for data-dependent sorting).

Memory management: The list nodes themselves are allocated and freed by the GSList APIs. By default, freeing a list with g_slist_free releases only the nodes; the data pointed to by each node is not freed automatically, so the caller must manage that memory or use an appropriate destroy function when freeing the elements (in supported GLib versions, a full/free_with-data variant may be available).

Relation to other types: GSList is the singly linked list variant in GLib. Its counterpart is GList, which implements a doubly linked list. Both types are widely used in GLib and GTK applications, offering different trade-offs for insertion, deletion, and traversal.

See also: GLib documentation for GSList and the related GList structure.