quarks.sgml

This GLib version 2.16.1. GLib is the low-level core library that forms the basis for projects such

<!-- ##### SECTION Title ##### -->
Quarks

<!-- ##### SECTION Short_Description ##### -->
a 2-way association between a string and a unique integer identifier

<!-- ##### SECTION Long_Description ##### -->
<para>
Quarks are associations between strings and integer identifiers.
Given either the string or the #GQuark identifier it is possible to
retrieve the other.
</para>
<para>
Quarks are used for both
<link linkend="glib-datasets">Datasets</link> and
<link linkend="glib-keyed-data-lists">Keyed Data Lists</link>.
</para>
<para>
To create a new quark from a string, use g_quark_from_string() or
g_quark_from_static_string().
</para>
<para>
To find the string corresponding to a given #GQuark, use g_quark_to_string().
</para>
<para>
To find the #GQuark corresponding to a given string, use g_quark_try_string().
</para>
<para>
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(). 
</para>

<!-- ##### SECTION See_Also ##### -->
<para>

</para>

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<!-- ##### TYPEDEF GQuark ##### -->
<para>
A GQuark is a non-zero integer which uniquely identifies a particular string.
A GQuark value of zero is associated to %NULL.
</para>


<!-- ##### FUNCTION g_quark_from_string ##### -->
<para>
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.
</para>

@string: a string.
@Returns: the #GQuark identifying the string, or 0 if @string is %NULL.


<!-- ##### FUNCTION g_quark_from_static_string ##### -->
<para>
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.
</para>
<para>
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
<emphasis>always</emphasis> 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).
</para>

@string: a string.
@Returns: the #GQuark identifying the string, or 0 if @string is %NULL.


<!-- ##### FUNCTION g_quark_to_string ##### -->
<para>
Gets the string associated with the given #GQuark.
</para>

@quark: a #GQuark.
@Returns: the string associated with the #GQuark.


<!-- ##### FUNCTION g_quark_try_string ##### -->
<para>
Gets the #GQuark associated with the given string, or 0 if string is
%NULL or it has no associated #GQuark.
</para>
<para>
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().
</para>

@string: a string.
@Returns: the #GQuark associated with the string, or 0 if @string is
%NULL or there is no #GQuark associated with it.


<!-- ##### FUNCTION g_intern_string ##### -->
<para>

</para>

@string: 
@Returns: 


<!-- ##### FUNCTION g_intern_static_string ##### -->
<para>

</para>

@string: 
@Returns: