GQuark

GQuark is a string interning facility used by GLib, the low-level core library of the GNOME platform. It provides a way to map strings to small, unique integers that can be compared quickly. In GLib, a GQuark is a typedef for guint32, representing a unique identifier for a string within the lifetime of a process.

Quarks are created on demand through functions such as g_quark_from_string, which registers a string in an internal table and returns its quark. If the same string is requested again, the same quark is returned, enabling fast, integer-based comparisons instead of repeated string comparisons. The function g_quark_to_string can be used to retrieve the original string from a quark, facilitating round trips between string form and quark form.

For performance and convenience, GLib also provides g_quark_from_static_string for strings with static storage duration. This variant registers the string without duplicating it and is intended for constant strings known at compile time.

Key characteristics and usage notes include that quarks are process-local and do not cross process boundaries; their primary benefit is speed and memory efficiency within a single running program. Quarks persist for the duration of the process, and the intern table is typically freed when the program exits. GQuark is widely used within GLib and GObject-based code to represent frequently compared strings, such as property names, error domains, and other identifiers, enabling faster comparisons and reduced string storage overhead.