Create a new process with the given flags and argument list.
The argument list is expected to be %NULL-terminated.
commandline arguments for the subprocess
flags that define the behaviour of the subprocess
Creates a binding between source_property
on source
and target_property
on target
.
Whenever the source_property
is changed the target_property
is
updated using the same value. For instance:
g_object_bind_property (action, "active", widget, "sensitive", 0);
Will result in the "sensitive" property of the widget #GObject instance to be updated with the same value of the "active" property of the action #GObject instance.
If flags
contains %G_BINDING_BIDIRECTIONAL then the binding will be mutual:
if target_property
on target
changes then the source_property
on source
will be updated as well.
The binding will automatically be removed when either the source
or the
target
instances are finalized. To remove the binding without affecting the
source
and the target
you can just call g_object_unref() on the returned
#GBinding instance.
Removing the binding by calling g_object_unref() on it must only be done if
the binding, source
and target
are only used from a single thread and it
is clear that both source
and target
outlive the binding. Especially it
is not safe to rely on this if the binding, source
or target
can be
finalized from different threads. Keep another reference to the binding and
use g_binding_unbind() instead to be on the safe side.
A #GObject can have multiple bindings.
the property on source
to bind
the target #GObject
the property on target
to bind
flags to pass to #GBinding
Creates a binding between source_property
on source
and target_property
on target,
allowing you to set the transformation functions to be used by
the binding.
This function is the language bindings friendly version of g_object_bind_property_full(), using #GClosures instead of function pointers.
the property on source
to bind
the target #GObject
the property on target
to bind
flags to pass to #GBinding
a #GClosure wrapping the transformation function from the source
to the target,
or %NULL to use the default
a #GClosure wrapping the transformation function from the target
to the source,
or %NULL to use the default
Communicate with the subprocess until it terminates, and all input and output has been completed.
If stdin_buf
is given, the subprocess must have been created with
%G_SUBPROCESS_FLAGS_STDIN_PIPE. The given data is fed to the
stdin of the subprocess and the pipe is closed (ie: EOF).
At the same time (as not to cause blocking when dealing with large
amounts of data), if %G_SUBPROCESS_FLAGS_STDOUT_PIPE or
%G_SUBPROCESS_FLAGS_STDERR_PIPE were used, reads from those
streams. The data that was read is returned in stdout
and/or
the stderr
.
If the subprocess was created with %G_SUBPROCESS_FLAGS_STDOUT_PIPE,
stdout_buf
will contain the data read from stdout. Otherwise, for
subprocesses not created with %G_SUBPROCESS_FLAGS_STDOUT_PIPE,
stdout_buf
will be set to %NULL. Similar provisions apply to
stderr_buf
and %G_SUBPROCESS_FLAGS_STDERR_PIPE.
As usual, any output variable may be given as %NULL to ignore it.
If you desire the stdout and stderr data to be interleaved, create
the subprocess with %G_SUBPROCESS_FLAGS_STDOUT_PIPE and
%G_SUBPROCESS_FLAGS_STDERR_MERGE. The merged result will be returned
in stdout_buf
and stderr_buf
will be set to %NULL.
In case of any error (including cancellation), %FALSE will be
returned with error
set. Some or all of the stdin data may have
been written. Any stdout or stderr data that has been read will be
discarded. None of the out variables (aside from error)
will have
been set to anything in particular and should not be inspected.
In the case that %TRUE is returned, the subprocess has exited and the exit status inspection APIs (eg: g_subprocess_get_if_exited(), g_subprocess_get_exit_status()) may be used.
You should not attempt to use any of the subprocess pipes after starting this function, since they may be left in strange states, even if the operation was cancelled. You should especially not attempt to interact with the pipes while the operation is in progress (either from another thread or if using the asynchronous version).
data to send to the stdin of the subprocess, or %NULL
a #GCancellable
Asynchronous version of g_subprocess_communicate(). Complete invocation with g_subprocess_communicate_finish().
Input data, or %NULL
Cancellable
Callback
Complete an invocation of g_subprocess_communicate_async().
Result
Like g_subprocess_communicate(), but validates the output of the process as UTF-8, and returns it as a regular NUL terminated string.
On error, stdout_buf
and stderr_buf
will be set to undefined values and
should not be used.
data to send to the stdin of the subprocess, or %NULL
a #GCancellable
Asynchronous version of g_subprocess_communicate_utf8(). Complete invocation with g_subprocess_communicate_utf8_finish().
Input data, or %NULL
Cancellable
Callback
Complete an invocation of g_subprocess_communicate_utf8_async().
Result
Use an operating-system specific method to attempt an immediate, forceful termination of the process. There is no mechanism to determine whether or not the request itself was successful; however, you can use g_subprocess_wait() to monitor the status of the process after calling this function.
On Unix, this function sends %SIGKILL.
This function is intended for #GObject implementations to re-enforce a [floating][floating-ref] object reference. Doing this is seldom required: all #GInitiallyUnowneds are created with a floating reference which usually just needs to be sunken by calling g_object_ref_sink().
Increases the freeze count on object
. If the freeze count is
non-zero, the emission of "notify" signals on object
is
stopped. The signals are queued until the freeze count is decreased
to zero. Duplicate notifications are squashed so that at most one
#GObject::notify signal is emitted for each property modified while the
object is frozen.
This is necessary for accessors that modify multiple properties to prevent premature notification while the object is still being modified.
Gets a named field from the objects table of associations (see g_object_set_data()).
name of the key for that association
Check the exit status of the subprocess, given that it exited normally. This is the value passed to the exit() system call or the return value from main.
This is equivalent to the system WEXITSTATUS macro.
It is an error to call this function before g_subprocess_wait() and unless g_subprocess_get_if_exited() returned %TRUE.
On UNIX, returns the process ID as a decimal string. On Windows, returns the result of GetProcessId() also as a string. If the subprocess has terminated, this will return %NULL.
Check if the given subprocess exited normally (ie: by way of exit() or return from main()).
This is equivalent to the system WIFEXITED macro.
It is an error to call this function before g_subprocess_wait() has returned.
Check if the given subprocess terminated in response to a signal.
This is equivalent to the system WIFSIGNALED macro.
It is an error to call this function before g_subprocess_wait() has returned.
Gets a property of an object.
The value
can be:
In general, a copy is made of the property contents and the caller is responsible for freeing the memory by calling g_value_unset().
Note that g_object_get_property() is really intended for language bindings, g_object_get() is much more convenient for C programming.
the name of the property to get
return location for the property value
This function gets back user data pointers stored via g_object_set_qdata().
A #GQuark, naming the user data pointer
Gets the raw status code of the process, as from waitpid().
This value has no particular meaning, but it can be used with the macros defined by the system headers such as WIFEXITED. It can also be used with g_spawn_check_wait_status().
It is more likely that you want to use g_subprocess_get_if_exited() followed by g_subprocess_get_exit_status().
It is an error to call this function before g_subprocess_wait() has returned.
Gets the #GInputStream from which to read the stderr output of
subprocess
.
The process must have been created with %G_SUBPROCESS_FLAGS_STDERR_PIPE, otherwise %NULL will be returned.
Gets the #GOutputStream that you can write to in order to give data
to the stdin of subprocess
.
The process must have been created with %G_SUBPROCESS_FLAGS_STDIN_PIPE and not %G_SUBPROCESS_FLAGS_STDIN_INHERIT, otherwise %NULL will be returned.
Gets the #GInputStream from which to read the stdout output of
subprocess
.
The process must have been created with %G_SUBPROCESS_FLAGS_STDOUT_PIPE, otherwise %NULL will be returned.
Checks if the process was "successful". A process is considered successful if it exited cleanly with an exit status of 0, either by way of the exit() system call or return from main().
It is an error to call this function before g_subprocess_wait() has returned.
Get the signal number that caused the subprocess to terminate, given that it terminated due to a signal.
This is equivalent to the system WTERMSIG macro.
It is an error to call this function before g_subprocess_wait() and unless g_subprocess_get_if_signaled() returned %TRUE.
Gets n_properties
properties for an object
.
Obtained properties will be set to values
. All properties must be valid.
Warnings will be emitted and undefined behaviour may result if invalid
properties are passed in.
the names of each property to get
the values of each property to get
Initializes the object implementing the interface.
This method is intended for language bindings. If writing in C, g_initable_new() should typically be used instead.
The object must be initialized before any real use after initial construction, either with this function or g_async_initable_init_async().
Implementations may also support cancellation. If cancellable
is not %NULL,
then initialization can be cancelled by triggering the cancellable object
from another thread. If the operation was cancelled, the error
%G_IO_ERROR_CANCELLED will be returned. If cancellable
is not %NULL and
the object doesn't support cancellable initialization the error
%G_IO_ERROR_NOT_SUPPORTED will be returned.
If the object is not initialized, or initialization returns with an error, then all operations on the object except g_object_ref() and g_object_unref() are considered to be invalid, and have undefined behaviour. See the [introduction][ginitable] for more details.
Callers should not assume that a class which implements #GInitable can be initialized multiple times, unless the class explicitly documents itself as supporting this. Generally, a class’ implementation of init() can assume (and assert) that it will only be called once. Previously, this documentation recommended all #GInitable implementations should be idempotent; that recommendation was relaxed in GLib 2.54.
If a class explicitly supports being initialized multiple times, it is recommended that the method is idempotent: multiple calls with the same arguments should return the same results. Only the first call initializes the object; further calls return the result of the first call.
One reason why a class might need to support idempotent initialization is if it is designed to be used via the singleton pattern, with a #GObjectClass.constructor that sometimes returns an existing instance. In this pattern, a caller would expect to be able to call g_initable_init() on the result of g_object_new(), regardless of whether it is in fact a new instance.
optional #GCancellable object, %NULL to ignore.
Checks whether object
has a [floating][floating-ref] reference.
Emits a "notify" signal for the property property_name
on object
.
When possible, eg. when signaling a property change from within the class that registered the property, you should use g_object_notify_by_pspec() instead.
Note that emission of the notify signal may be blocked with g_object_freeze_notify(). In this case, the signal emissions are queued and will be emitted (in reverse order) when g_object_thaw_notify() is called.
the name of a property installed on the class of object
.
Emits a "notify" signal for the property specified by pspec
on object
.
This function omits the property name lookup, hence it is faster than g_object_notify().
One way to avoid using g_object_notify() from within the class that registered the properties, and using g_object_notify_by_pspec() instead, is to store the GParamSpec used with g_object_class_install_property() inside a static array, e.g.:
enum
{
PROP_0,
PROP_FOO,
PROP_LAST
};
static GParamSpec *properties[PROP_LAST];
static void
my_object_class_init (MyObjectClass *klass)
{
properties[PROP_FOO] = g_param_spec_int ("foo", "Foo", "The foo",
0, 100,
50,
G_PARAM_READWRITE);
g_object_class_install_property (gobject_class,
PROP_FOO,
properties[PROP_FOO]);
}
and then notify a change on the "foo" property with:
g_object_notify_by_pspec (self, properties[PROP_FOO]);
the #GParamSpec of a property installed on the class of object
.
Increase the reference count of object,
and possibly remove the
[floating][floating-ref] reference, if object
has a floating reference.
In other words, if the object is floating, then this call "assumes ownership" of the floating reference, converting it to a normal reference by clearing the floating flag while leaving the reference count unchanged. If the object is not floating, then this call adds a new normal reference increasing the reference count by one.
Since GLib 2.56, the type of object
will be propagated to the return type
under the same conditions as for g_object_ref().
Releases all references to other objects. This can be used to break reference cycles.
This function should only be called from object system implementations.
Sends the UNIX signal signal_num
to the subprocess, if it is still
running.
This API is race-free. If the subprocess has terminated, it will not be signalled.
This API is not available on Windows.
the signal number to send
Each object carries around a table of associations from strings to pointers. This function lets you set an association.
If the object already had an association with that name, the old association will be destroyed.
Internally, the key
is converted to a #GQuark using g_quark_from_string().
This means a copy of key
is kept permanently (even after object
has been
finalized) — so it is recommended to only use a small, bounded set of values
for key
in your program, to avoid the #GQuark storage growing unbounded.
name of the key
data to associate with that key
Sets a property on an object.
the name of the property to set
the value
Remove a specified datum from the object's data associations, without invoking the association's destroy handler.
name of the key
This function gets back user data pointers stored via
g_object_set_qdata() and removes the data
from object
without invoking its destroy() function (if any was
set).
Usually, calling this function is only required to update
user data pointers with a destroy notifier, for example:
void
object_add_to_user_list (GObject *object,
const gchar *new_string)
{
// the quark, naming the object data
GQuark quark_string_list = g_quark_from_static_string ("my-string-list");
// retrieve the old string list
GList *list = g_object_steal_qdata (object, quark_string_list);
// prepend new string
list = g_list_prepend (list, g_strdup (new_string));
// this changed 'list', so we need to set it again
g_object_set_qdata_full (object, quark_string_list, list, free_string_list);
}
static void
free_string_list (gpointer data)
{
GList *node, *list = data;
for (node = list; node; node = node->next)
g_free (node->data);
g_list_free (list);
}
Using g_object_get_qdata() in the above example, instead of g_object_steal_qdata() would have left the destroy function set, and thus the partial string list would have been freed upon g_object_set_qdata_full().
A #GQuark, naming the user data pointer
Reverts the effect of a previous call to
g_object_freeze_notify(). The freeze count is decreased on object
and when it reaches zero, queued "notify" signals are emitted.
Duplicate notifications for each property are squashed so that at most one #GObject::notify signal is emitted for each property, in the reverse order in which they have been queued.
It is an error to call this function when the freeze count is zero.
Decreases the reference count of object
. When its reference count
drops to 0, the object is finalized (i.e. its memory is freed).
If the pointer to the #GObject may be reused in future (for example, if it is an instance variable of another object), it is recommended to clear the pointer to %NULL rather than retain a dangling pointer to a potentially invalid #GObject instance. Use g_clear_object() for this.
Initializes the object implementing the interface.
This method is intended for language bindings. If writing in C, g_initable_new() should typically be used instead.
The object must be initialized before any real use after initial construction, either with this function or g_async_initable_init_async().
Implementations may also support cancellation. If cancellable
is not %NULL,
then initialization can be cancelled by triggering the cancellable object
from another thread. If the operation was cancelled, the error
%G_IO_ERROR_CANCELLED will be returned. If cancellable
is not %NULL and
the object doesn't support cancellable initialization the error
%G_IO_ERROR_NOT_SUPPORTED will be returned.
If the object is not initialized, or initialization returns with an error, then all operations on the object except g_object_ref() and g_object_unref() are considered to be invalid, and have undefined behaviour. See the [introduction][ginitable] for more details.
Callers should not assume that a class which implements #GInitable can be initialized multiple times, unless the class explicitly documents itself as supporting this. Generally, a class’ implementation of init() can assume (and assert) that it will only be called once. Previously, this documentation recommended all #GInitable implementations should be idempotent; that recommendation was relaxed in GLib 2.54.
If a class explicitly supports being initialized multiple times, it is recommended that the method is idempotent: multiple calls with the same arguments should return the same results. Only the first call initializes the object; further calls return the result of the first call.
One reason why a class might need to support idempotent initialization is if it is designed to be used via the singleton pattern, with a #GObjectClass.constructor that sometimes returns an existing instance. In this pattern, a caller would expect to be able to call g_initable_init() on the result of g_object_new(), regardless of whether it is in fact a new instance.
optional #GCancellable object, %NULL to ignore.
Emits a "notify" signal for the property property_name
on object
.
When possible, eg. when signaling a property change from within the class that registered the property, you should use g_object_notify_by_pspec() instead.
Note that emission of the notify signal may be blocked with g_object_freeze_notify(). In this case, the signal emissions are queued and will be emitted (in reverse order) when g_object_thaw_notify() is called.
Synchronously wait for the subprocess to terminate.
After the process terminates you can query its exit status with functions such as g_subprocess_get_if_exited() and g_subprocess_get_exit_status().
This function does not fail in the case of the subprocess having abnormal termination. See g_subprocess_wait_check() for that.
Cancelling cancellable
doesn't kill the subprocess. Call
g_subprocess_force_exit() if it is desirable.
a #GCancellable
Wait for the subprocess to terminate.
This is the asynchronous version of g_subprocess_wait().
a #GCancellable, or %NULL
a #GAsyncReadyCallback to call when the operation is complete
Combines g_subprocess_wait() with g_spawn_check_wait_status().
a #GCancellable
Combines g_subprocess_wait_async() with g_spawn_check_wait_status().
This is the asynchronous version of g_subprocess_wait_check().
a #GCancellable, or %NULL
a #GAsyncReadyCallback to call when the operation is complete
Collects the result of a previous call to g_subprocess_wait_check_async().
the #GAsyncResult passed to your #GAsyncReadyCallback
Collects the result of a previous call to g_subprocess_wait_async().
the #GAsyncResult passed to your #GAsyncReadyCallback
This function essentially limits the life time of the closure
to
the life time of the object. That is, when the object is finalized,
the closure
is invalidated by calling g_closure_invalidate() on
it, in order to prevent invocations of the closure with a finalized
(nonexisting) object. Also, g_object_ref() and g_object_unref() are
added as marshal guards to the closure,
to ensure that an extra
reference count is held on object
during invocation of the
closure
. Usually, this function will be called on closures that
use this object
as closure data.
#GClosure to watch
Find the #GParamSpec with the given name for an
interface. Generally, the interface vtable passed in as g_iface
will be the default vtable from g_type_default_interface_ref(), or,
if you know the interface has already been loaded,
g_type_default_interface_peek().
any interface vtable for the interface, or the default vtable for the interface
name of a property to look up.
Add a property to an interface; this is only useful for interfaces that are added to GObject-derived types. Adding a property to an interface forces all objects classes with that interface to have a compatible property. The compatible property could be a newly created #GParamSpec, but normally g_object_class_override_property() will be used so that the object class only needs to provide an implementation and inherits the property description, default value, bounds, and so forth from the interface property.
This function is meant to be called from the interface's default
vtable initialization function (the class_init
member of
#GTypeInfo.) It must not be called after after class_init
has
been called for any object types implementing this interface.
If pspec
is a floating reference, it will be consumed.
any interface vtable for the interface, or the default vtable for the interface.
the #GParamSpec for the new property
Lists the properties of an interface.Generally, the interface
vtable passed in as g_iface
will be the default vtable from
g_type_default_interface_ref(), or, if you know the interface has
already been loaded, g_type_default_interface_peek().
any interface vtable for the interface, or the default vtable for the interface
Create a new process with the given flags and argument list.
The argument list is expected to be %NULL-terminated.
commandline arguments for the subprocess
flags that define the behaviour of the subprocess
Creates a new instance of a #GObject subtype and sets its properties.
Construction parameters (see %G_PARAM_CONSTRUCT, %G_PARAM_CONSTRUCT_ONLY) which are not explicitly specified are set to their default values.
the type id of the #GObject subtype to instantiate
an array of #GParameter
#GSubprocess allows the creation of and interaction with child processes.
Processes can be communicated with using standard GIO-style APIs (ie: #GInputStream, #GOutputStream). There are GIO-style APIs to wait for process termination (ie: cancellable and with an asynchronous variant).
There is an API to force a process to terminate, as well as a race-free API for sending UNIX signals to a subprocess.
One major advantage that GIO brings over the core GLib library is comprehensive API for asynchronous I/O, such g_output_stream_splice_async(). This makes GSubprocess significantly more powerful and flexible than equivalent APIs in some other languages such as the
subprocess.py
included with Python. For example, using #GSubprocess one could create two child processes, reading standard output from the first, processing it, and writing to the input stream of the second, all without blocking the main loop.A powerful g_subprocess_communicate() API is provided similar to the
communicate()
method ofsubprocess.py
. This enables very easy interaction with a subprocess that has been opened with pipes.#GSubprocess defaults to tight control over the file descriptors open in the child process, avoiding dangling-fd issues that are caused by a simple fork()/exec(). The only open file descriptors in the spawned process are ones that were explicitly specified by the #GSubprocess API (unless %G_SUBPROCESS_FLAGS_INHERIT_FDS was specified).
#GSubprocess will quickly reap all child processes as they exit, avoiding "zombie processes" remaining around for long periods of time. g_subprocess_wait() can be used to wait for this to happen, but it will happen even without the call being explicitly made.
As a matter of principle, #GSubprocess has no API that accepts shell-style space-separated strings. It will, however, match the typical shell behaviour of searching the PATH for executables that do not contain a directory separator in their name. By default, the
PATH
of the current process is used. You can specify %G_SUBPROCESS_FLAGS_SEARCH_PATH_FROM_ENVP to use thePATH
of the launcher environment instead.#GSubprocess attempts to have a very simple API for most uses (ie: spawning a subprocess with arguments and support for most typical kinds of input and output redirection). See g_subprocess_new(). The #GSubprocessLauncher API is provided for more complicated cases (advanced types of redirection, environment variable manipulation, change of working directory, child setup functions, etc).
A typical use of #GSubprocess will involve calling g_subprocess_new(), followed by g_subprocess_wait_async() or g_subprocess_wait(). After the process exits, the status can be checked using functions such as g_subprocess_get_if_exited() (which are similar to the familiar WIFEXITED-style POSIX macros).