Try harder to explain GApplicationCommandline

Trying to answer some of the questions in
https://bugzilla.gnome.org/show_bug.cgi?id=643468

gio/tests/Makefile.am

@@ -90,6 +90,7 @@ SAMPLE_PROGS = 				\
 	gapplication-example-open	\
 	gapplication-example-cmdline	\
 	gapplication-example-cmdline2	\
+	gapplication-example-cmdline3	\
 	gapplication-example-actions	\
 	$(NULL)
 
@@ -328,6 +329,9 @@ gapplication_example_cmdline_LDADD   = $(progs_ldadd)
 gapplication_example_cmdline2_SOURCES = gapplication-example-cmdline2.c
 gapplication_example_cmdline2_LDADD   = $(progs_ldadd)
 
+gapplication_example_cmdline3_SOURCES = gapplication-example-cmdline3.c
+gapplication_example_cmdline3_LDADD   = $(progs_ldadd)
+
 gapplication_example_actions_SOURCES = gapplication-example-actions.c
 gapplication_example_actions_LDADD   = $(progs_ldadd)
 

gio/tests/gapplication-example-cmdline3.c

@@ -0,0 +1,65 @@
+#include <gio/gio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static gboolean
+my_cmdline_handler (gpointer data)
+{
+  GApplicationCommandLine *cmdline = data;
+  gchar **argv;
+  gint argc;
+  gint i;
+
+  argv = g_application_command_line_get_arguments (cmdline, &argc);
+
+  g_application_command_line_print (cmdline,
+                                    "This text is written back\n"
+                                    "to stdout of the caller\n");
+
+  for (i = 0; i < argc; i++)
+    g_print ("argument %d: %s\n", i, argv[i]);
+
+  g_strfreev (argv);
+
+  g_application_command_line_set_exit_status (cmdline, 1);
+
+  /* we are done handling this commandline */
+  g_object_unref (cmdline);
+
+  return FALSE;
+}
+
+static int
+command_line (GApplication            *application,
+              GApplicationCommandLine *cmdline)
+{
+  /* keep the application running until we are done with this commandline */
+  g_application_hold (application);
+
+  g_object_set_data_full (G_OBJECT (cmdline),
+                          "application", application,
+                          (GDestroyNotify)g_application_release);
+
+  g_object_ref (cmdline);
+  g_idle_add (my_cmdline_handler, cmdline);
+
+  return 0;
+}
+
+int
+main (int argc, char **argv)
+{
+  GApplication *app;
+  int status;
+
+  app = g_application_new ("org.gtk.TestApplication",
+                           G_APPLICATION_HANDLES_COMMAND_LINE);
+  g_signal_connect (app, "command-line", G_CALLBACK (command_line), NULL);
+  g_application_set_inactivity_timeout (app, 10000);
+
+  status = g_application_run (app, argc, argv);
+
+  g_object_unref (app);
+
+  return status;
+}