gtk/docs/reference/gdk/tmpl/input.sgml

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1999-08-16 18:51:52 +00:00
<!-- ##### SECTION Title ##### -->
Input
<!-- ##### SECTION Short_Description ##### -->
Callbacks on file descriptors.
<!-- ##### SECTION Long_Description ##### -->
<para>
The functions in this section are used to establish
callbacks when some condition becomes true for
a file descriptor. They are currently just wrappers around
the <link linkend="glib-IO-Channels">IO Channel</link>
facility.
</para>
<!-- ##### SECTION See_Also ##### -->
<para>
<variablelist>
<varlistentry>
<term><link linkend="glib-The-Main-Event-Loop">GLib Main Loop</link></term>
<listitem><para>The main loop in which input callbacks run.</para></listitem>
</varlistentry>
<varlistentry>
<term><link linkend="glib-IO-Channels">IO Channels</link></term>
<listitem><para>A newer and more flexible way of doing IO
callbacks.</para></listitem>
</varlistentry>
</variablelist>
</para>
<!-- ##### FUNCTION gdk_input_add_full ##### -->
<para>
Establish a callback when a condition becomes true on
a file descriptor.
</para>
@source: a file descriptor.
@condition: the condition.
@function: the callback function.
@data: callback data passed to @function.
@destroy: callback function to call with @data when the input
handler is removed.
@Returns: a tag that can later be used as an argument to
gdk_input_remove().
<!-- ##### ENUM GdkInputCondition ##### -->
<para>
A set of bit flags used to specify conditions for which
an input callback will be triggered. The three members
of this enumeration correspond to the @readfds,
@writefds, and @exceptfds arguments to the
<function>select</function> system call.
<informaltable pgwide=1 frame="none" role="enum">
<tgroup cols="2"><colspec colwidth="2*"><colspec colwidth="8*">
<tbody>
<row>
<entry>GDK_INPUT_READ</entry>
<entry>the file descriptor has become available for reading.
(Or, as is standard in Unix, a socket or pipe was closed
at the other end; this is the case if a subsequent read
on the file descriptor returns a count of zero.)</entry>
</row>
<row>
<entry>GDK_INPUT_WRITE</entry>
<entry>the file descriptor has become available for writing.</entry>
</row>
<row>
<entry>GDK_INPUT_EXCEPTION</entry>
<entry>an exception was raised on the file descriptor.</entry>
</row>
</tbody></tgroup></informaltable>
</para>
@GDK_INPUT_READ:
@GDK_INPUT_WRITE:
@GDK_INPUT_EXCEPTION:
<!-- ##### USER_FUNCTION GdkInputFunction ##### -->
<para>
A callback function that will be called when some condition
occurs.
</para>
@data: the user data passed to gdk_input_add() or gdk_input_add_full().
@source: the source where the condition occurred.
@condition: the triggering condition.
<!-- ##### USER_FUNCTION GdkDestroyNotify ##### -->
<para>
A callback function called when a piece of user data is
no longer being stored by GDK. Will typically free the
structure or object that @data points to.
</para>
@data: the user data.
<!-- ##### FUNCTION gdk_input_add ##### -->
<para>
Establish a callback when a condition becomes true on
a file descriptor.
</para>
@source: a file descriptor.
@condition: the condition.
@function: the callback function.
@data: callback data passed to @function.
@Returns: a tag that can later be used as an argument to
gdk_input_remove().
<!-- ##### FUNCTION gdk_input_remove ##### -->
<para>
Remove a callback added with gdk_input_add() or
gdk_input_add_full().
</para>
@tag: the tag returned when the callback was set up.