z79.html

gtk_text program sample&eg

            </p>
            <p>
              <code><code class="FUNCDEF">gchar* <tt class=
              "FUNCTION">
              gnome_config_get_translated_string_with_default</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>,
              gboolean* <tt class="PARAMETER"><i>
              was_default</i></tt>);</code>
            </p>
            <p>
              <code><code class="FUNCDEF">gint <tt class=
              "FUNCTION">
              gnome_config_get_int_with_default</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>,
              gboolean* <tt class="PARAMETER"><i>
              was_default</i></tt>);</code>
            </p>
            <p>
              <code><code class="FUNCDEF">gdouble <tt class= 
              "FUNCTION">
              gnome_config_get_float_with_default</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>,
              gboolean* <tt class="PARAMETER"><i>
              was_default</i></tt>);</code>
            </p>
            <p>
              <code><code class="FUNCDEF">gboolean <tt class= 
              "FUNCTION">
              gnome_config_get_bool_with_default</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>,
              gboolean* <tt class="PARAMETER"><i>
              was_default</i></tt>);</code>
            </p>
            <p>
              <code><code class="FUNCDEF">void <tt class=
              "FUNCTION">
              gnome_config_get_vector_with_default</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>, gint*
              <tt class="PARAMETER"><i>argcp</i></tt>, gchar*** <tt
              class="PARAMETER"><i>argvp</i></tt>, gboolean* <tt
              class="PARAMETER"><i>was_default</i></tt>);</code>
            </p>
            <p>
              <code><code class="FUNCDEF">gchar* <tt class=
              "FUNCTION">
              gnome_config_private_get_string_with_default</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>,
              gboolean* <tt class="PARAMETER"><i>
              was_default</i></tt>);</code>
            </p>
            <p>
              <code><code class="FUNCDEF">gchar* <tt class=
              "FUNCTION">
              gnome_config_private_get_translated_string_with_default</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>,
              gboolean* <tt class="PARAMETER"><i>
              was_default</i></tt>);</code>
            </p>
            <p>
              <code><code class="FUNCDEF">gint <tt class=
              "FUNCTION">
              gnome_config_private_get_int_with_default</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>,
              gboolean* <tt class="PARAMETER"><i>
              was_default</i></tt>);</code>
            </p>
            <p>
              <code><code class="FUNCDEF">gdouble <tt class= 
              "FUNCTION">
              gnome_config_private_get_float_with_default</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>,
              gboolean* <tt class="PARAMETER"><i>
              was_default</i></tt>);</code>
            </p>
            <p>
              <code><code class="FUNCDEF">gboolean <tt class= 
              "FUNCTION">
              gnome_config_private_get_bool_with_default</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>,
              gboolean* <tt class="PARAMETER"><i>
              was_default</i></tt>);</code>
            </p>
            <p>
              <code><code class="FUNCDEF">void <tt class=
              "FUNCTION">
              gnome_config_private_get_vector_with_default</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>, gint*
              <tt class="PARAMETER"><i>argcp</i></tt>, gchar*** <tt
              class="PARAMETER"><i>argvp</i></tt>, gboolean* <tt
              class="PARAMETER"><i>was_default</i></tt>);</code>
            </p>
          </div>
          <p>
            <b>Figure 4. Retrieving data from configuration
            files</b>
          </p>
        </div>
      </div>
      <div class="SECT2">
        <h2 class="SECT2">
          <a name="Z81">Storing Data In Configuration Files</a>
        </h2>
        <p>
          Saving data is simply the inverse of loading it; you
          provide a <span class="STRUCTNAME">
          "/file/section/key"</span> path in just the same way,
          along with the value to store. Data is not written
          immediately; you must call <tt class="FUNCTION">
          gnome_config_sync()</tt> to ensure the file is written to
          disk.
        </p>
        <div class="FIGURE">
          <a name="STARTUP-GNOMECONFIGSET"></a>
          <div class="FUNCSYNOPSIS">
            <a name="STARTUP-GNOMECONFIGSET.SYNOPSIS"></a>
            <table border="0" bgcolor="#E0E0E0" width="100%">
              <tr>
                <td>
<pre class="FUNCSYNOPSISINFO">
#include &lt;libgnome/gnome-config.h&gt;
</pre>
                </td>
              </tr>
            </table>
            <p>
              <code><code class="FUNCDEF">void <tt class=
              "FUNCTION">gnome_config_set_string</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>, const
              gchar* <tt class="PARAMETER"><i>
              value</i></tt>);</code>
            </p>
            <p>
              <code><code class="FUNCDEF">void <tt class=
              "FUNCTION">
              gnome_config_set_translated_string</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>, const
              gchar* <tt class="PARAMETER"><i>
              value</i></tt>);</code>
            </p>
            <p>
              <code><code class="FUNCDEF">void <tt class=
              "FUNCTION">gnome_config_set_int</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>, gint
              <tt class="PARAMETER"><i>value</i></tt>);</code>
            </p>
            <p>
              <code><code class="FUNCDEF">void <tt class=
              "FUNCTION">gnome_config_set_float</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>,
              gdouble <tt class="PARAMETER"><i>
              value</i></tt>);</code>
            </p>
            <p>
              <code><code class="FUNCDEF">void <tt class=
              "FUNCTION">gnome_config_set_bool</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>,
              gboolean <tt class="PARAMETER"><i>
              value</i></tt>);</code>
            </p>
            <p>
              <code><code class="FUNCDEF">void <tt class=
              "FUNCTION">gnome_config_set_vector</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>, gint
              <tt class="PARAMETER"><i>argc</i></tt>, const gchar*
              const <tt class="PARAMETER"><i>
              argv[]</i></tt>);</code>
            </p>
            <p>
              <code><code class="FUNCDEF">void <tt class=
              "FUNCTION">
              gnome_config_private_set_string</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>, const
              gchar* <tt class="PARAMETER"><i>
              value</i></tt>);</code>
            </p>
            <p>
              <code><code class="FUNCDEF">void <tt class=
              "FUNCTION">
              gnome_config_private_set_translated_string</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>, const
              gchar* <tt class="PARAMETER"><i>
              value</i></tt>);</code>
            </p>
            <p>
              <code><code class="FUNCDEF">void <tt class=
              "FUNCTION">
              gnome_config_private_set_int</tt></code>(const gchar*
              <tt class="PARAMETER"><i>path</i></tt>, gint <tt
              class="PARAMETER"><i>value</i></tt>);</code>
            </p>
            <p>
              <code><code class="FUNCDEF">void <tt class=
              "FUNCTION">
              gnome_config_private_set_float</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>,
              gdouble <tt class="PARAMETER"><i>
              value</i></tt>);</code>
            </p>
            <p>
              <code><code class="FUNCDEF">void <tt class=
              "FUNCTION">
              gnome_config_private_set_bool</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>,
              gboolean <tt class="PARAMETER"><i>
              value</i></tt>);</code>
            </p>
            <p>
              <code><code class="FUNCDEF">void <tt class=
              "FUNCTION">
              gnome_config_private_set_vector</tt></code>(const
              gchar* <tt class="PARAMETER"><i>path</i></tt>, gint
              <tt class="PARAMETER"><i>argc</i></tt>, const gchar*
              const <tt class="PARAMETER"><i>
              argv[]</i></tt>);</code>
            </p>
          </div>
          <p>
            <b>Figure 5. Saving data to configuration files</b>
          </p>
        </div>
      </div>
      <div class="SECT2">
        <h2 class="SECT2">
          <a name="Z82">Config File Iterators</a>
        </h2>
        <p>
          Iterators are used to scan the sections in a given file,
          or the keys in a given section. Applications can use this
          feature to store lists of data, by dynamically generating
          key or section names to save and later iterating over
          them to discover what was saved. The functions are
          summarized in <a href= 
          "z79.html#STARTUP-GNOMECONFIGITERATORS">Figure 6 in the
          section called <i>Section Iterators</i></a>.
        </p>
        <p>
          An iterator is an opaque data type; you pass <tt class= 
          "FUNCTION">gnome_config_init_iterator()</tt> the name of
          a section to iterate over and receive an iterator in
          return. You then call <tt class="FUNCTION">
          gnome_config_iterator_next()</tt> to obtain key-value
          pairs from the section. The key and value returned from
          <tt class="FUNCTION">gnome_config_iterator_next()</tt>
          must be freed with <tt class="FUNCTION">g_free()</tt>,
          and the return value of <tt class="FUNCTION">
          gnome_config_iterator_next()</tt> is a pointer to the
          next iterator. When <tt class="FUNCTION">
          gnome_config_iterator_next()</tt> returns <span class= 
          "STRUCTNAME">NULL</span>, all key-value pairs have been
          traversed.
        </p>
        <div class="SECT3">
          <h3 class="SECT3">
            <a name="Z83">Iteration Example from <tt class= 
            "APPLICATION">gnome-apt</tt></a>
          </h3>
          <p>
            Here's an example from <tt class="APPLICATION">
            gnome-apt</tt>, a C++ application used to manage
            packages on Debian systems. <tt class="APPLICATION">
            gnome-apt</tt> loads and saves the position of some
            columns in a tree display. The columns are identified
            by the <span class="STRUCTNAME">
            GAptPkgTree::ColumnType</span> enumeration. <span
            class="STRUCTNAME">GAptPkgTree::ColumnTypeEnd</span> is
            the last element in the column type enumeration, and
            equal to the number of valid column types. This example
            is frighteningly "real world" and checks for a number
            of error conditions.
          </p>
          <table border="0" bgcolor="#E0E0E0" width="100%">
            <tr>
              <td>
<pre class="PROGRAMLISTING">
&#13;static void
load_column_order(vector&lt;GAptPkgTree::ColumnType&gt; &amp; columns)
{
  gpointer config_iterator;
  guint loaded = 0;

  config_iterator = gnome_config_init_iterator("/gnome-apt/ColumnOrder");

  if (config_iterator != 0)
    {
      gchar * col, * pos;
      columns.reserve(GAptPkgTree::ColumnTypeEnd);
      
      loaded = 0;
      while ((config_iterator = 
              gnome_config_iterator_next(config_iterator, 
                                         &amp;col, &amp;pos))) 
        {
          // shouldn't happen, but I'm paranoid
          if (pos == 0 || col == 0)
            {
              if (pos) g_free(pos);
              if (col) g_free(col);
              continue;
            }
          
          GAptPkgTree::ColumnType ct = string_to_column(col);
          
          gint index = atoi(pos);

          g_free(pos); pos = 0;
          g_free(col); col = 0;
          
          // the user could mangle the config file to make this happen
          if (static_cast&lt;guint&gt;(index) &gt;= columns.size()) 
            continue;
          
          columns[index] = ct;
          
          ++loaded;
        }
    }

  if (loaded != static_cast&lt;guint&gt;(GAptPkgTree::ColumnTypeEnd))
    {
      // Either there was no saved order, or something is busted - use
      // default order
      columns.clear();
      
      int i = 0;
      while (i &lt; GAptPkgTree::ColumnTypeEnd)
        {
          columns.push_back(static_cast&lt;GAptPkgTree::ColumnType&gt;(i));
          ++i;
        }

      // Clean the section - otherwise an old entry could 
      //  remain forever and keep screwing us up in the future.
      gnome_config_clean_section("/gnome-apt/ColumnOrder");
      gnome_config_sync();
    }
  
  g_return_if_fail(columns.size() == 
                   static_cast&lt;guint&gt;(GAptPkgTree::ColumnTypeEnd));
}&#13;
</pre>
              </td>
            </tr>
          </table>
          <p>
            It might be helpful to see the function that saves the
            column positions:
          </p>
          <table border="0" bgcolor="#E0E0E0" width="100%">