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    GtkWidget *label2;

    label1 = gtk_label_new (_("Another string to translate"));
    label2 = gtk_label_new (_(global_variable));
...
</pre></div>
<p>
</p>
<p>
Libraries using gettext should use <code class="function">dgettext()</code> instead of <code class="function">gettext()</code>, which 
allows them to specify the translation domain each time they ask for a 
translation. Libraries should also avoid calling <code class="function">textdomain()</code>, since they
will be specifying the domain instead of using the default. For <code class="function">dgettext()</code> 
the <code class="function">_()</code> macro can be defined as:
</p>
<div class="informalexample"><pre class="programlisting">
  #define _(x) dgettext ("MyDomain", x)
</pre></div>
<p>
</p>
<p>
Again, GLib comes with the <code class="filename">gi18n-lib.h</code>, saving you the 
trouble of defining the macros by hand. The macros in that header expect the 
translation domain to be specified by the <code class="literal">GETTEXT_PACKAGE</code> macro. 
</p>
</td>
</tr>
<tr class="question">
<td align="left" valign="top">
<a name="id3137091"></a><a name="id3137093"></a><p><b>1.8.</b></p>
</td>
<td align="left" valign="top"><p>
How do I use non-ASCII characters in GTK+ programs ?
</p></td>
</tr>
<tr class="answer">
<td align="left" valign="top"></td>
<td align="left" valign="top">
<p>
GTK+ uses <a class="ulink" href="http://www.unicode.org" target="_top">Unicode</a> (more exactly 
UTF-8) for all text. UTF-8 encodes each Unicode codepoint as a sequence of 
one to six bytes and has a number of nice properties which make it a good 
choice for working with Unicode text in C programs:
</p>
<div class="itemizedlist"><ul type="disc">
<li><p>
ASCII characters are encoded by their familiar ASCII codepoints.
</p></li>
<li><p>
ASCII characters never appear as part of any other character.
</p></li>
<li><p>
The zero byte doesn't occur as part of a character, so that UTF-8 strings 
can be manipulated with the usual C library functions for handling 
zero-terminated strings.
</p></li>
</ul></div>
<p>
More information about Unicode and UTF-8 can be found in the 
<a class="ulink" href="http://www.cl.cam.ac.uk/~mgk25/unicode.html" target="_top">UTF-8 and Unicode i
FAQ for Unix/Linux</a>.
GLib provides functions for converting strings between UTF-8 and other
encodings, see <a
href="/usr/share/gtk-doc/html/glib/glib-Character-Set-Conversion.html#g-locale-to-utf8"
><code class="function">g_locale_to_utf8()</code></a> and <a
href="/usr/share/gtk-doc/html/glib/glib-Character-Set-Conversion.html#g-convert"
><code class="function">g_convert()</code></a>.
</p>
<p>
Text coming from external sources (e.g. files or user input), has to be
converted to UTF-8 before being handed over to GTK+. The following example 
writes the content of a IS0-8859-1 encoded text file to 
<code class="literal">stdout</code>:
</p>
<div class="informalexample"><pre class="programlisting">
gchar *text, *utf8_text;
gsize length;
GError *error = NULL;

if (g_file_get_contents (filename, &amp;text, &amp;length, NULL)) 
  {
     utf8_text = g_convert (text, length, "UTF-8", "ISO-8859-1", 
                            NULL, NULL, &amp;error);
     if (error != NULL)
       {
         fprintf ("Couldn't convert file %s to UTF-8\n", filename);
         g_error_free (error);
       }
     else
       g_print (utf8_text);
  }
else 
  fprintf (stderr, "Unable to read file %s\n", filename);
</pre></div>
<p>
</p>
<p>
For string literals in the source code, there are several alternatives for
handling non-ASCII content:
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term">direct UTF-8</span></p></td>
<td><p>
If your editor and compiler are capable of handling UTF-8 encoded sources,
it is very convenient to simply use UTF-8 for string literals, since it allows
you to edit the strings in "wysiwyg". Note that choosing this option may 
reduce the portability of your code.  
</p></td>
</tr>
<tr>
<td><p><span class="term">escaped UTF-8</span></p></td>
<td><p>
Even if your toolchain can't handle UTF-8 directly, you can still encode string
literals in UTF-8 by using octal or hexadecimal escapes like 
<code class="literal">\212</code> or <code class="literal">\xa8</code> to
encode each byte. This is portable, but modifying the escaped strings is not
very convenient. Be careful when mixing hexadecimal escapes with ordinary text;
<code class="literal">"\xa8abcd"</code> is a string of length 1 !
</p></td>
</tr>
<tr>
<td><p><span class="term">runtime conversion</span></p></td>
<td><p>
If the string literals can be represented in an encoding which your toolchain
can handle (e.g. IS0-8859-1), you can write your source files in that encoding
and use <a
href="/usr/share/gtk-doc/html/glib/glib-Character-Set-Conversion.html#g-convert"
><code class="function">g_convert()</code></a> to convert the strings to UTF-8 at runtime. Note that this 
has some runtime overhead, so you may want to move the conversion out of inner 
loops.
</p></td>
</tr>
</tbody>
</table></div>
<p>
Here is an example showing the three approaches using the copyright sign 
&#169; which has Unicode and ISO-8859-1 codepoint 169 and is represented in
UTF-8 by the two bytes 194, 169:
</p>
<div class="informalexample"><pre class="programlisting">
g_print ("direct UTF-8: &#169;");
g_print ("escaped UTF-8: \302\251");
text = g_convert ("runtime conversion: &#169;", -1, "ISO-8859-1", "UTF-8", NULL, NULL, NULL);
g_print(text);
g_free (text);
</pre></div>
<p>
</p>
</td>
</tr>
<tr class="question">
<td align="left" valign="top">
<a name="id3137290"></a><a name="id3137292"></a><p><b>1.9.</b></p>
</td>
<td align="left" valign="top"><p>
How do I use GTK+ with C++?
</p></td>
</tr>
<tr class="answer">
<td align="left" valign="top"></td>
<td align="left" valign="top">
<p>
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 <a class="ulink" href="http://gtkmm.sourceforge.net/" target="_top">gtkmm</a>
which provides a native C++ API.
</p>
<p>
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.
</p>
<p>
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:
</p>
<div class="informalexample"><pre class="programlisting">
  gdk_window_set_events (gdk_window, 
                         GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK);
</pre></div>
<p>
while in C++ you must write:
</p>
<div class="informalexample"><pre class="programlisting">
  gdk_window_set_events (gdk_window, 
                         (GdkEventMask) GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK);
</pre></div>
<p>
There are very few functions that require this cast, however.
</p>
</td>
</tr>
<tr class="question">
<td align="left" valign="top">
<a name="id3137352"></a><a name="id3137355"></a><p><b>1.10.</b></p>
</td>
<td align="left" valign="top"><p>
How do I use GTK+ with other non-C languages?
</p></td>
</tr>
<tr class="answer">
<td align="left" valign="top"></td>
<td align="left" valign="top"><p>
See the <a class="ulink" href="http://www.gtk.org/bindings.html" target="_top">list of language
bindings</a> on <a class="ulink" href="http://www.gtk.org" target="_top">http://www.gtk.org</a>.
</p></td>
</tr>
<tr class="question">
<td align="left" valign="top">
<a name="id3137381"></a><a name="id3137383"></a><p><b>1.11.</b></p>
</td>
<td align="left" valign="top"><p>
How do I load an image or animation from a file?
</p></td>
</tr>
<tr class="answer">
<td align="left" valign="top"></td>
<td align="left" valign="top">
<p>
To load an image file straight into a display widget, use 
<a class="link" href="GtkImage.html#gtk-image-new-from-file"><code class="function">gtk_image_new_from_file()</code></a> <sup>[<a name="id3137402" href="#ftn.id3137402" class="footnote">1</a>]</sup>. 
To load an image for another purpose, use <a
href="/usr/share/gtk-doc/html/gdk-pixbuf/gdk-pixbuf-file-loading.html#gdk-pixbuf-new-from-file"
><code class="function">gdk_pixbuf_new_from_file()</code></a>. To i
load an animation, use <a
href="/usr/share/gtk-doc/html/gdk-pixbuf/gdk-pixbuf-animation.html#gdk-pixbuf-animation-new-from-file"
><code class="function">gdk_pixbuf_animation_new_from_file()</code></a>.
<a
href="/usr/share/gtk-doc/html/gdk-pixbuf/gdk-pixbuf-animation.html#gdk-pixbuf-animation-new-from-file"
><code class="function">gdk_pixbuf_animation_new_from_file()</code></a> can also load non-animated images, so 
use it in combination with <a
href="/usr/share/gtk-doc/html/gdk-pixbuf/gdk-pixbuf-animation.html#gdk-pixbuf-animation-is-static-image"
><code class="function">gdk_pixbuf_animation_is_static_image()</code></a> to load a 
file of unknown type. 
</p>
<p>
To load an image or animation file asynchronously (without blocking), use 
<a
href="/usr/share/gtk-doc/html/gdk-pixbuf/GdkPixbufLoader.html"
><span class="type">GdkPixbufLoader</span></a>.
</p>
</td>
</tr>
<tr class="question">
<td align="left" valign="top">
<a name="id3137499"></a><a name="id3137501"></a><p><b>1.12.</b></p>
</td>
<td align="left" valign="top"><p>
How do I draw text ?
</p></td>
</tr>
<tr class="answer">
<td align="left" valign="top"></td>
<td align="left" valign="top">
<p>
To draw a piece of text, use a Pango layout and <a
href="/usr/share/gtk-doc/html/gdk/gdk-Drawing-Primitives.html#gdk-draw-layout"
><code class="function">gdk_draw_layout()</code></a>, 
using code like the following:
</p>
<div class="informalexample"><pre class="programlisting">
 layout = gtk_widget_create_pango_layout (widget, text);
 fontdesc = pango_font_description_from_string ("Luxi Mono 12");
 pango_layout_set_font_description (layout, fontdesc); 
 gdk_draw_layout (..., layout);
 pango_font_description_free (fontdesc);
 g_object_unref (layout);
</pre></div>
<p>
Do not use the deprecated <a
href="/usr/share/gtk-doc/html/gdk/gdk-Fonts.html#GdkFont"
><span class="type">GdkFont</span></a> and <a
href="/usr/share/gtk-doc/html/gdk/gdk-Drawing-Primitives.html#gdk-draw-text"
><code class="function">gdk_draw_text()</code></a>.
</p>
<p>
See also the "Text Handling in GTK 2" section of 
<a class="ulink" href="http://developer.gnome.org/dotplan/porting/" target="_top">Porting applications 
to the GNOME 2.0 platform</a>.
</p>
</td>
</tr>
<tr class="question">
<td align="left" valign="top">
<a name="id3137570"></a><a name="id3137573"></a><p><b>1.13.</b></p>
</td>
<td align="left" valign="top"><p>
How do I measure the size of a piece of text ?
</p></td>
</tr>
<tr class="answer">
<td align="left" valign="top"></td>
<td align="left" valign="top">
<p>
To obtain the size of a piece of text, use a Pango layout and 
<a
href="/usr/share/gtk-doc/html/pango/pango-Layout-Objects.html#pango-layout-get-pixel-size"
><code class="function">pango_layout_get_pixel_size()</code></a>, using code like the following:
</p>
<div class="informalexample"><pre class="programlisting">
 layout = gtk_widget_create_pango_layout (widget, text);
 fontdesc = pango_font_description_from_string ("Luxi Mono 12");
 pango_layout_set_font_description (layout, fontdesc); 
 pango_layout_get_pixel_size (layout, &amp;width, &amp;height);
 pango_font_description_free (fontdesc);
 g_object_unref (layout);
</pre></div>
<p>
Do not use the deprecated function <a
href="/usr/share/gtk-doc/html/gdk/gdk-Fonts.html#gdk-text-width"
><code class="function">gdk_text_width()</code></a>.
</p>
<p>