Quarks

Quarks — a 2-way association between a string and a unique integer identifier

Synopsis


#include <glib.h>


typedef             GQuark;
GQuark              g_quark_from_string                 (const gchar *string);
GQuark              g_quark_from_static_string          (const gchar *string);
const gchar*        g_quark_to_string                   (GQuark quark);
GQuark              g_quark_try_string                  (const gchar *string);
const gchar*        g_intern_string                     (const gchar *string);
const gchar*        g_intern_static_string              (const gchar *string);

Description

Quarks are associations between strings and integer identifiers. Given either the string or the GQuark identifier it is possible to retrieve the other.

Quarks are used for both Datasets and Keyed Data Lists.

To create a new quark from a string, use g_quark_from_string() or g_quark_from_static_string().

To find the string corresponding to a given GQuark, use g_quark_to_string().

To find the GQuark corresponding to a given string, use g_quark_try_string().

Another use for the string pool maintained for the quark functions is string interning, using g_intern_string() or g_intern_static_string(). An interned string is a canonical representation for a string. One important advantage of interned strings is that they can be compared for equality by a simple pointer comparision, rather than using strcmp().

Details

GQuark

typedef guint32 GQuark;

A GQuark is a non-zero integer which uniquely identifies a particular string. A GQuark value of zero is associated to NULL.

g_quark_from_string ()

GQuark              g_quark_from_string                 (const gchar *string);

Gets the GQuark identifying the given string. If the string does not currently have an associated GQuark, a new GQuark is created, using a copy of the string.

string :

 a string.

Returns :

 the GQuark identifying the string, or 0 if string is NULL.

g_quark_from_static_string ()

GQuark              g_quark_from_static_string          (const gchar *string);

Gets the GQuark identifying the given (static) string. If the string does not currently have an associated GQuark, a new GQuark is created, linked to the given string.

Note that this function is identical to g_quark_from_string() except that if a new GQuark is created the string itself is used rather than a copy. This saves memory, but can only be used if the string will always exist. It can be used with statically allocated strings in the main program, but not with statically allocated memory in dynamically loaded modules, if you expect to ever unload the module again (e.g. do not use this function in GTK+ theme engines).

string :

 a string.

Returns :

 the GQuark identifying the string, or 0 if string is NULL.

g_quark_to_string ()

const gchar*        g_quark_to_string                   (GQuark quark);

Gets the string associated with the given GQuark.

quark :

 a GQuark.

Returns :

 the string associated with the GQuark.

g_quark_try_string ()

GQuark              g_quark_try_string                  (const gchar *string);

Gets the GQuark associated with the given string, or 0 if string is NULL or it has no associated GQuark.

If you want the GQuark to be created if it doesn't already exist, use g_quark_from_string() or g_quark_from_static_string().

string :

 a string.

Returns :

 the GQuark associated with the string, or 0 if string is NULL or there is no GQuark associated with it.

g_intern_string ()

const gchar*        g_intern_string                     (const gchar *string);

Returns a canonical representation for string. Interned strings can be compared for equality by comparing the pointers, instead of using strcmp().

string :

 a string

Returns :

 a canonical representation for the string

Since 2.10

g_intern_static_string ()

const gchar*        g_intern_static_string              (const gchar *string);

Returns a canonical representation for string. Interned strings can be compared for equality by comparing the pointers, instead of using strcmp(). g_intern_static_string() does not copy the string, therefore string must not be freed or modified.

string :

 a static string

Returns :

 a canonical representation for the string

Since 2.10