Class

GioApplicationCommandLine

Description [src]

class Gio.ApplicationCommandLine : GObject.Object {
  /* No available fields */
}

GApplicationCommandLine represents a command-line invocation of an application. It is created by GApplication and emitted in the GApplication::command-line signal and virtual function.

The class contains the list of arguments that the program was invoked with. It is also possible to query if the commandline invocation was local (ie: the current process is running in direct response to the invocation) or remote (ie: some other process forwarded the commandline to this process).

The GApplicationCommandLine object can provide the argc and argv parameters for use with the GOptionContext command-line parsing API, with the g_application_command_line_get_arguments() function. See [gapplication-example-cmdline3.c][gapplication-example-cmdline3] for an example.

The exit status of the originally-invoked process may be set and messages can be printed to stdout or stderr of that process. The lifecycle of the originally-invoked process is tied to the lifecycle of this object (ie: the process exits when the last reference is dropped).

The main use for GApplicationCommandLine (and the GApplication::command-line signal) is ‘Emacs server’ like use cases: You can set the EDITOR environment variable to have e.g. git use your favourite editor to edit commit messages, and if you already have an instance of the editor running, the editing will happen in the running instance, instead of opening a new one. An important aspect of this use case is that the process that gets started by git does not return until the editing is done.

Normally, the commandline is completely handled in the GApplication::command-line handler. The launching instance exits once the signal handler in the primary instance has returned, and the return value of the signal handler becomes the exit status of the launching instance.

static int
command_line (GApplication            *application,
              GApplicationCommandLine *cmdline)
{
  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);

  return 0;
}

The complete example can be found here: gapplication-example-cmdline.c

In more complicated cases, the handling of the comandline can be split between the launcher and the primary instance.

static gboolean
 test_local_cmdline (GApplication   *application,
                     gchar        ***arguments,
                     gint           *exit_status)
{
  gint i, j;
  gchar **argv;

  argv = *arguments;

  i = 1;
  while (argv[i])
    {
      if (g_str_has_prefix (argv[i], "--local-"))
        {
          g_print ("handling argument %s locally\n", argv[i]);
          g_free (argv[i]);
          for (j = i; argv[j]; j++)
            argv[j] = argv[j + 1];
        }
      else
        {
          g_print ("not handling argument %s locally\n", argv[i]);
          i++;
        }
    }

  *exit_status = 0;

  return FALSE;
}

static void
test_application_class_init (TestApplicationClass *class)
{
  G_APPLICATION_CLASS (class)->local_command_line = test_local_cmdline;

  ...
}

In this example of split commandline handling, options that start with --local- are handled locally, all other options are passed to the GApplication::command-line handler which runs in the primary instance.

The complete example can be found here: gapplication-example-cmdline2.c

If handling the commandline requires a lot of work, it may be better to defer it.

static gboolean
my_cmdline_handler (gpointer data)
{
  GApplicationCommandLine *cmdline = data;

  // do the heavy lifting in an idle

  g_application_command_line_set_exit_status (cmdline, 0);
  g_object_unref (cmdline); // this releases the application

  return G_SOURCE_REMOVE;
}

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;
}

In this example the commandline is not completely handled before the GApplication::command-line handler returns. Instead, we keep a reference to the GApplicationCommandLine object and handle it later (in this example, in an idle). Note that it is necessary to hold the application until you are done with the commandline.

The complete example can be found here: gapplication-example-cmdline3.c

Hierarchy

hierarchy this GApplicationCommandLine ancestor_0 GObject ancestor_0--this

Ancestors

Instance methods

g_application_command_line_create_file_for_arg

Creates a GFile corresponding to a filename that was given as part of the invocation of cmdline.

Available since: 2.36

g_application_command_line_get_arguments

Gets the list of arguments that was passed on the command line.

Available since: 2.28

g_application_command_line_get_cwd

Gets the working directory of the command line invocation. The string may contain non-utf8 data.

Available since: 2.28

g_application_command_line_get_environ

Gets the contents of the ‘environ’ variable of the command line invocation, as would be returned by g_get_environ(), ie as a NULL-terminated list of strings in the form ‘NAME=VALUE’. The strings may contain non-utf8 data.

Available since: 2.28

g_application_command_line_get_exit_status

Gets the exit status of cmdline. See g_application_command_line_set_exit_status() for more information.

Available since: 2.28

g_application_command_line_get_is_remote

Determines if cmdline represents a remote invocation.

Available since: 2.28

g_application_command_line_get_options_dict

Gets the options there were passed to g_application_command_line().

Available since: 2.40

g_application_command_line_get_platform_data

Gets the platform data associated with the invocation of cmdline.

Available since: 2.28

g_application_command_line_get_stdin

Gets the stdin of the invoking process.

Available since: 2.34

g_application_command_line_getenv

Gets the value of a particular environment variable of the command line invocation, as would be returned by g_getenv(). The strings may contain non-utf8 data.

Available since: 2.28

g_application_command_line_print

Formats a message and prints it using the stdout print handler in the invoking process.

Available since: 2.28

g_application_command_line_printerr

Formats a message and prints it using the stderr print handler in the invoking process.

Available since: 2.28

g_application_command_line_set_exit_status

Sets the exit status that will be used when the invoking process exits.

Available since: 2.28

Methods inherited from GObject (43)

Properties

Gio.ApplicationCommandLine:arguments
No description available.
Gio.ApplicationCommandLine:is-remote
No description available.
Gio.ApplicationCommandLine:options
No description available.
Gio.ApplicationCommandLine:platform-data
No description available.

Signals

Signals inherited from GObject (1)

Class structure

struct GioApplicationCommandLineClass {
  void (* print_literal) (
    GApplicationCommandLine* cmdline,
    const gchar* message
  );
  void (* printerr_literal) (
    GApplicationCommandLine* cmdline,
    const gchar* message
  );
  GInputStream* (* get_stdin) (
    GApplicationCommandLine* cmdline
  );
  
}
Class members
print_literal
void (* print_literal) (
    GApplicationCommandLine* cmdline,
    const gchar* message
  )
  No description available.
printerr_literal
void (* printerr_literal) (
    GApplicationCommandLine* cmdline,
    const gchar* message
  )
  No description available.
get_stdin
GInputStream* (* get_stdin) (
    GApplicationCommandLine* cmdline
  )
  No description available.

Virtual methods

Gio.ApplicationCommandLineClass.get_stdin

Gets the stdin of the invoking process.

Available since: 2.34