Quarks

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

Types and Values

typedef GQuark

Includes

#include <glib.h>

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 comparison, rather than using strcmp().

Functions

G_DEFINE_QUARK()

#define             G_DEFINE_QUARK(QN, q_n)

A convenience macro which defines a function returning the GQuark for the name QN . The function will be named q_n_quark() .

Note that the quark name will be stringified automatically in the macro, so you shouldn't use double quotes.

Parameters

QN

the name to return a GQuark for

 

q_n

prefix for the function name

 

Since: 2.34


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.

Parameters

string

a string.

[allow-none]

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 continue to exist until the program terminates. 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).

Parameters

string

a string.

[allow-none]

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.

Parameters

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().

Parameters

string

a string.

[allow-none]

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().

Parameters

string

a string.

[allow-none]

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.

Parameters

string

a static string.

[allow-none]

Returns

a canonical representation for the string

Since: 2.10

Types and Values

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.