cdesktop/cde/doc/C/guides/dtkshGuide/ch02.sgm

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<chapter id="DKSUG.scr1.div.1">
<title>A Sample Script<indexterm><primary>script</primary><secondary>sample</secondary></indexterm><indexterm><primary>sample script</primary></indexterm></title>
<para>This chapter shows you how to use what you learned about <command>dtksh</command> in Chapter 1. The two simple scripts described here should give
you a good start at writing your own scripts.</para>
<sect1 id="DKSUG.scr1.div.2">
<title>Writing the Script<indexterm><primary>script</primary><secondary>writing</secondary></indexterm></title>
<para>This script creates a bulletin board widget within which a push button
widget is placed. The script is kept simple by not including any callbacks.
The second script includes a callback.</para>
<para>Here's the first script:</para>
<programlisting>#!/usr/dt/bin/dtksh
XtInitialize TOPLEVEL dttest1 Dtksh $0<indexterm><primary>XtInitialize</primary>
</indexterm>
XtSetValues $TOPLEVEL title:&ldquo;dttest1&rdquo;<indexterm><primary>XtSetValues</primary></indexterm>
XtCreateManagedWidget BBOARD bboard XmBulletinBoard $TOPLEVEL \
   resizePolicy:RESIZE_NONE height:150 width:250\
   background:SkyBlue<indexterm><primary>XtCreateManagedWidget</primary></indexterm>
XtCreateManagedWidget BUTTON pushbutton XmPushButton $BBOARD \<indexterm>
<primary>XtCreateManagedWidget</primary></indexterm>
   background:goldenrod \
   foreground:MidnightBlue \
   labelString:&rdquo;Push Here&rdquo; \
   height:30 width:100 x:75 y:60 shadowThickness:3
XtRealizeWidget $TOPLEVEL<indexterm><primary>XtRealizeWidget</primary></indexterm>XtMainLoop<indexterm>
<primary>XtMainLoop</primary></indexterm></programlisting>
<para>Figure 2-1 shows the window that the first script produces.</para>
<figure>
<title>Window from script dttest</title>
<graphic id="DKSUG.scr1.grph.1" entityref="DKSUG.scr1.fig.1"></graphic>
</figure>
<para>The first line of the script:</para>
<programlisting>#!/usr/dt/bin/dtksh</programlisting>
<para>tells the operating system that this script should be executed using
<filename>/usr/dt/bin/dtksh</filename> rather than the standard shell.</para>
<para>The next line initializes the Xt Intrinsics.<indexterm><primary>initialize</primary></indexterm></para>
<para>XtInitialize TOPLEVEL dttest1 Dtksh $0</para>
<para>The name of the<indexterm><primary>toplevel widget</primary></indexterm><indexterm>
<primary>widget</primary><secondary>toplevel</secondary></indexterm> top-level
widget is saved in the environment variable <filename>$TOPLEVEL</filename>,
the shell widget name is <filename>dttest1</filename>, the application class
name is <filename>Dtksh,</filename> and the application name is given by
the <command>dtksh</command> variable <filename>$0</filename>.</para>
<para>The next line sets the title resource to the name of the script.</para>
<programlisting>XtSetValues $TOPLEVEL title:&rdquo;dttest1&rdquo;</programlisting>
<para>Notice that there is no space between the colon after the resource name
(title) and its value. An error message appears if you have a space between
them.</para>
<para>The next four lines create a<indexterm><primary>bulletin board</primary>
</indexterm><indexterm><primary>widget</primary><secondary>bulletin board</secondary></indexterm> bulletin board widget and set some of its resources.
</para>
<programlisting>XtCreateManagedWidget BBOARD bboard XmBbulletinBoard $TOPLEVEL \
  resizePolicy:RESIZE_NONE \
  background:SkyBlue\
  height:150 width:250</programlisting>
<para>The bulletin board widget's ID is saved in the environment variable <filename>$BBOARD</filename>. The widget's name is <command>bboard</command>. This
name is used by the Xt Intrinsics to set the values of resources that might
be named in an external resource file. The widget class is <command>XmBulletinBoard</command>. The bulletin board's parent widget is the widget ID contained
in the environment variable <filename>$TOPLEVEL</filename>. This is the topl-
evel widget created by the initializion command in the first line. The \
(backslash) at the end of the line tells <command>dtksh</command> that this
command continues on the next line.</para>
<para>The next six lines create a<indexterm><primary>pushbutton</primary>
</indexterm><indexterm><primary>widget</primary><secondary>pushbutton</secondary>
</indexterm> push button widget as a child of the bulletin board, and set
some of the push button's resources.</para>
<programlisting>XtCreateManagedWidget BUTTON pushbutton XmPushButton $BBOARD \
  background:goldenrod \
  foreground:MidnightBlue \
  labelString:&rdquo;Push Here&rdquo;\
  height:30 width:100 x:75 y:60\
  shadowThickness:3</programlisting>
<para>This is basically the same procedure used to create the bulletin board,
except that the variable, name, class, and parent are different.</para>
<para>The next line causes the toplevel widget and all its children to be
realized.</para>
<programlisting>XtRealizeWidget $TOPLEVEL<indexterm><primary>XtrealizeWidget</primary></indexterm></programlisting>
<para>Finally, the<indexterm><primary>XtMainLoop</primary></indexterm> <command>XtMainLoop</command> command initiates a loop processing of events for the
widgets.</para>
<programlisting>XtMainLoop</programlisting>
<para>In this script, all that happens is the window appears on the display.
It stays there until you terminate the script, either by choosing <command>Close</command> on the Window Manager menu or by pressing CTRL C in the terminal
window from which you executed the script.</para>
</sect1>
<sect1 id="DKSUG.scr1.div.3">
<title>Adding a Callback<indexterm><primary>callback</primary></indexterm></title>
<para>To provide a function for the push button so that when it is pressed
a message appears in the terminal window and the script terminates, you have
to add a callback. Also, you must tell the push button about the existence
of this callback. The following is the script with the new code added:</para>
<programlisting>#!/usr/dt/bin/dtksh

activateCB() {
 echo &ldquo;Pushbutton activated; normal termination.&rdquo;
 exit 0
}

XtInitialize TOPLEVEL dttest2 Dtksh $0
XtSetValues $TOPLEVEL title:&rdquo;dttest2&rdquo;
XtCreateManagedWidget BBOARD bboard XmBulletinBoard $TOPLEVEL \
  resizePolicy:RESIZE_NONE \
  background:SkyBlue \
  height:150 width:250
XtCreateManagedWidget BUTTON pushbutton XmPushButton $BBOARD \
  background:goldenrod \
  foreground:MidnightBlue \
  labelString:&rdquo;Push Here&rdquo;\
  height:30 width:100 x:75 y:60 shadowThickness:3

XtAddCallback $BUTTON activateCallback activateCB
XtRealizeWidget $TOPLEVEL
XtMainLoop</programlisting>
<para>The callback is the function <filename>activateCB()</filename>. You
typically add the callback to the push button after it (the push button)
has been created:</para>
<programlisting>XtAddCallback $BUTTON activateCallback activateCB</programlisting>
<para>Now the pushbutton knows about the callback. When you click the push
button, the function <filename>activateCB()</filename> is executed, and the
message &ldquo;<command>Pushbutton activated; normal termination.</command>&rdquo;
appears in the terminal window from which you executed the script. The script
is terminated by the call to the function <command>exit 0</command>.</para>
</sect1>
</chapter>
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