Commit ef121a06 authored by Havoc Pennington's avatar Havoc Pennington Committed by Havoc Pennington
Browse files

a few more questions I thought of

2002-01-06  Havoc Pennington  <hp@pobox.com>

	* gtk/question_index.sgml: a few more questions I thought of
parent 824e8e2d
2002-01-06 Havoc Pennington <hp@pobox.com>
* gtk/question_index.sgml: a few more questions I thought of
2002-01-06 Havoc Pennington <hp@pobox.com>
* gtk/gtk-docs.sgml: remove gtk- prefix from TreeView and a few
......
......@@ -122,6 +122,138 @@ threading primitives.
</qandaentry>
<qandaentry>
<question><para>
How do I internationalize a GTK+ program?
</para></question>
<answer>
<para>
Most people use <ulink url="http://www.gnu.org/software/gettext/">GNU
gettext</ulink>, already required in order to install GLib. On a UNIX
or Linux system with gettext installed, type <literal>info
gettext</literal> to read the documentation.
</para>
<para>
The short checklist on how to use gettext is: call
<function>bindtextdomain()</function> so gettext can find the files
containing your translations, call <function>textdomain()</function>
to set the default translation domain, then call
<function>gettext()</function> to look up each string to be translated
in the default domain. Conventionally, people define macros as
follows for convenience:
<informalexample>
<programlisting>
#define _(x) gettext (x)
#define N_(x) x
</programlisting>
</informalexample>
You use <function>N_()</function> (N stands for no-op) to mark
a string for translation in a context where a function call
to <function>gettext()</function> is not allowed, such as in
an array initializer. You eventually have to call
<function>gettext()</function> on the string to actually fetch the
translation. <function>_()</function> both marks the string for
translation and actually translates it.
</para>
<para>
Code using these macros ends up looking like this:
<informalexample>
<programlisting>
#include &lt;libintl.h&gt;
#define _(x) gettext (x)
#define N_(x) x
static const char *global_variable = N_("Translate this string");
static void
make_widgets (void)
{
GtkWidget *label1;
GtkWidget *label2;
label1 = gtk_label_new (_("Another string to translate"));
label2 = gtk_label_new (_(global_variable));
...
</programlisting>
</informalexample>
</para>
<para>
Libraries using gettext should use <function>dgettext()</function>
instead of <function>gettext()</function>, which allows
them to specify the translation domain each time they
ask for a translation. Libraries should also avoid calling
<function>textdomain()</function>, since they'll be specifying
the domain instead of using the default.
For <function>dgettext()</function> the <function>_()</function> macro
can be defined as:
<informalexample>
<programlisting>
#define _(x) dgettext ("MyDomain", x)
</programlisting>
</informalexample>
</para>
</answer>
</qandaentry>
<qandaentry>
<question><para>
How do I use GTK+ with C++?
</para></question>
<answer>
<para>
There are two ways to approach this. The GTK+ header files use the subset
of C that's also valid C++, so you can simply use the normal GTK+ API
in a C++ program. Alternatively, you can use a "C++ binding"
such as <ulink url="http://gtkmm.sourceforge.net/">gtkmm</ulink>
which provides a C++-native API.
</para>
<para>
When using GTK+ directly, keep in mind that only functions can be
connected to signals, not methods. So you will need to use global
functions or "static" class functions for signal connections.
</para>
<para>
Another common issue when using GTK+ directly is that
C++ will not implicitly convert an integer to an enumeration.
This comes up when using bitfields; in C you can write the following
code:
<informalexample>
<programlisting>
gdk_window_set_events (gdk_window,
GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK);
</programlisting>
</informalexample>
while in C++ you must write:
<informalexample>
<programlisting>
gdk_window_set_events (gdk_window,
(GdkEventMask) GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK);
</programlisting>
</informalexample>
There are very few functions that require this cast, however.
</para>
</answer>
</qandaentry>
<qandaentry>
<question><para>
How do I use GTK+ with other non-C languages?
</para></question>
<answer>
<para>
See the <ulink url="http://www.gtk.org/bindings.html">list of language
bindings</ulink> on <ulink
url="http://www.gtk.org">http://www.gtk.org</ulink>.
</para>
</answer>
</qandaentry>
<qandaentry>
<question><para>
......
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