class Gio::ApplicationCommandLine

Overview

#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 commandline 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;

if (argv[0] == NULL) { *exit_status = 0; return FALSE; }

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

Defined in:

lib/gi-crystal/src/auto/gio-2.0/application_command_line.cr

Constructors

Class Method Summary

Instance Method Summary

Instance methods inherited from class GObject::Object

==(other : self) ==, bind_property(source_property : String, target : GObject::Object, target_property : String, flags : GObject::BindingFlags) : GObject::Binding bind_property, bind_property_full(source_property : String, target : GObject::Object, target_property : String, flags : GObject::BindingFlags, transform_to : GObject::Closure, transform_from : GObject::Closure) : GObject::Binding bind_property_full, data(key : String) : Pointer(Void) | Nil data, finalize finalize, freeze_notify : Nil freeze_notify, getv(names : Enumerable(String), values : Enumerable(_)) : Nil getv, hash(hasher) hash, notify(property_name : String) : Nil notify, notify_by_pspec(pspec : GObject::ParamSpec) : Nil notify_by_pspec, notify_signal notify_signal, property(property_name : String, value : _) : Nil property, qdata(quark : UInt32) : Pointer(Void) | Nil qdata, ref_count : UInt32 ref_count, run_dispose : Nil run_dispose, set_data(key : String, data : Pointer(Void) | Nil) : Nil set_data, set_property(property_name : String, value : _) : Nil set_property, steal_data(key : String) : Pointer(Void) | Nil steal_data, steal_qdata(quark : UInt32) : Pointer(Void) | Nil steal_qdata, thaw_notify : Nil thaw_notify, to_unsafe : Pointer(Void) to_unsafe, watch_closure(closure : GObject::Closure) : Nil watch_closure

Constructor methods inherited from class GObject::Object

cast(obj : GObject::Object) : self cast, new(pointer : Pointer(Void), transfer : GICrystal::Transfer)
new
new
, newv(object_type : UInt64, parameters : Enumerable(GObject::Parameter)) : self newv

Class methods inherited from class GObject::Object

cast?(obj : GObject::Object) : self | Nil cast?, compat_control(what : UInt64, data : Pointer(Void) | Nil) : UInt64 compat_control, g_type : UInt64 g_type, interface_find_property(g_iface : GObject::TypeInterface, property_name : String) : GObject::ParamSpec interface_find_property, interface_list_properties(g_iface : GObject::TypeInterface) : Enumerable(GObject::ParamSpec) interface_list_properties

Constructor Detail

def self.new #

Initialize a new ApplicationCommandLine.


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def self.new(*, arguments : GLib::Variant | Nil = nil, is_remote : Bool | Nil = nil, options : GLib::Variant | Nil = nil, platform_data : GLib::Variant | Nil = nil) #

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Class Method Detail

def self.g_type : UInt64 #

Returns the type id (GType) registered in GLib type system.


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Instance Method Detail

def ==(other : self) #
Description copied from class Reference

Returns true if this reference is the same as other. Invokes same?.


def arguments : Enumerable(String) #

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

The strings in the array may contain non-UTF-8 data on UNIX (such as filenames or arguments given in the system locale) but are always in UTF-8 on Windows.

If you wish to use the return value with #GOptionContext, you must use g_option_context_parse_strv().

The return value is nil-terminated and should be freed using g_strfreev().


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def arguments=(value : GLib::Variant | Nil) : GLib::Variant | Nil #

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def create_file_for_arg(arg : String) : Gio::File #

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

This differs from g_file_new_for_commandline_arg() in that it resolves relative pathnames using the current working directory of the invoking process rather than the local process.


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def cwd : Path | Nil #

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

It is possible that the remote application did not send a working directory, so this may be nil.

The return value should not be modified or freed and is valid for as long as cmdline exists.


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def environ : Enumerable(String) #

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

The remote application usually does not send an environment. Use %G_APPLICATION_SEND_ENVIRONMENT to affect that. Even with this flag set it is possible that the environment is still not available (due to invocation messages from other applications).

The return value should not be modified or freed and is valid for as long as cmdline exists.

See g_application_command_line_getenv() if you are only interested in the value of a single environment variable.


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def exit_status : Int32 #

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


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def exit_status=(exit_status : Int32) : Nil #

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

The return value of the #GApplication::command-line signal is passed to this function when the handler returns. This is the usual way of setting the exit status.

In the event that you want the remote invocation to continue running and want to decide on the exit status in the future, you can use this call. For the case of a remote invocation, the remote process will typically exit when the last reference is dropped on cmdline. The exit status of the remote process will be equal to the last value that was set with this function.

In the case that the commandline invocation is local, the situation is slightly more complicated. If the commandline invocation results in the mainloop running (ie: because the use-count of the application increased to a non-zero value) then the application is considered to have been 'successful' in a certain sense, and the exit status is always zero. If the application use count is zero, though, the exit status of the local #GApplicationCommandLine is used.


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def getenv(name : String) : String | Nil #

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.

The remote application usually does not send an environment. Use %G_APPLICATION_SEND_ENVIRONMENT to affect that. Even with this flag set it is possible that the environment is still not available (due to invocation messages from other applications).

The return value should not be modified or freed and is valid for as long as cmdline exists.


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def hash(hasher) #
Description copied from class Reference

See Object#hash(hasher)


def is_remote : Bool #

Determines if cmdline represents a remote invocation.


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def is_remote? : Bool #

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def options=(value : GLib::Variant | Nil) : GLib::Variant | Nil #

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def options_dict : GLib::VariantDict #

Gets the options there were passed to g_application_command_line().

If you did not override local_command_line() then these are the same options that were parsed according to the #GOptionEntrys added to the application with g_application_add_main_option_entries() and possibly modified from your GApplication::handle-local-options handler.

If no options were sent then an empty dictionary is returned so that you don't need to check for nil.


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def platform_data : GLib::Variant | Nil #

Gets the platform data associated with the invocation of cmdline.

This is a #GVariant dictionary containing information about the context in which the invocation occurred. It typically contains information like the current working directory and the startup notification ID.

For local invocation, it will be nil.


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def platform_data=(value : GLib::Variant | Nil) : GLib::Variant | Nil #

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def stdin : Gio::InputStream | Nil #

Gets the stdin of the invoking process.

The #GInputStream can be used to read data passed to the standard input of the invoking process. This doesn't work on all platforms. Presently, it is only available on UNIX when using a D-Bus daemon capable of passing file descriptors. If stdin is not available then nil will be returned. In the future, support may be expanded to other platforms.

You must only call this function once per commandline invocation.


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