Gio.Subprocess¶

Subclasses:: None

Methods¶

Inherited:: GObject.Object (37), Gio.Initable (2)
Structs:: GObject.ObjectClass (5)

class	`new` (argv, flags)
	`communicate` (stdin_buf, cancellable)
	`communicate_async` (stdin_buf, cancellable, callback, *user_data)
	`communicate_finish` (result)
	`communicate_utf8` (stdin_buf, cancellable)
	`communicate_utf8_async` (stdin_buf, cancellable, callback, *user_data)
	`communicate_utf8_finish` (result)
	`force_exit` ()
	`get_exit_status` ()
	`get_identifier` ()
	`get_if_exited` ()
	`get_if_signaled` ()
	`get_status` ()
	`get_stderr_pipe` ()
	`get_stdin_pipe` ()
	`get_stdout_pipe` ()
	`get_successful` ()
	`get_term_sig` ()
	`send_signal` (signal_num)
	`wait` (cancellable)
	`wait_async` (cancellable, callback, *user_data)
	`wait_check` (cancellable)
	`wait_check_async` (cancellable, callback, *user_data)
	`wait_check_finish` (result)
	`wait_finish` (result)

Virtual Methods¶

Inherited:: GObject.Object (7), Gio.Initable (1)

Properties¶

Name	Type	Flags	Short Description
`argv`	[`str`]	w/co
`flags`	`Gio.SubprocessFlags`	w/co

Signals¶

Inherited:: GObject.Object (1)

Fields¶

Inherited:: GObject.Object (1)

Class Details¶

class Gio.Subprocess(**kwargs)¶

Bases:: GObject.Object, Gio.Initable
Abstract:: No

GSubprocess allows the creation of and interaction with child processes.

Processes can be communicated with using standard GIO-style APIs (ie: [class`Gio`.InputStream], [class`Gio`.OutputStream]). 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 [method`Gio`.OutputStream.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 [method`Gio`.Subprocess.communicate] API is provided similar to the communicate() method of subprocess.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. [method`Gio`.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 the PATH 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 [ctor`Gio`.Subprocess.new]. The [class`Gio`.SubprocessLauncher] 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 [ctor`Gio`.Subprocess.new], followed by [method`Gio`.Subprocess.wait_async] or [method`Gio`.Subprocess.wait]. After the process exits, the status can be checked using functions such as [method`Gio`.Subprocess.get_if_exited] (which are similar to the familiar WIFEXITED-style POSIX macros).

New in version 2.40.

classmethod new(argv, flags)[source]¶

Parameters:

argv ([str]) – commandline arguments for the subprocess
flags (Gio.SubprocessFlags) – flags that define the behaviour of the subprocess

Raises:

GLib.Error

Returns:

A newly created Gio.Subprocess, or None on error (and error will be set)

Return type:

Gio.Subprocess

Create a new process with the given flags and argument list.

The argument list is expected to be None-terminated.

New in version 2.40.

communicate(stdin_buf, cancellable)[source]¶

Parameters:

stdin_buf (GLib.Bytes or None) – data to send to the stdin of the subprocess, or None
cancellable (Gio.Cancellable or None) – a Gio.Cancellable

Raises:

GLib.Error

Returns:

True if successful

stdout_buf:: data read from the subprocess stdout
stderr_buf:: data read from the subprocess stderr

Return type:

(bool, stdout_buf: GLib.Bytes or None, stderr_buf: GLib.Bytes or None)

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 Gio.SubprocessFlags.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 Gio.SubprocessFlags.STDOUT_PIPE or Gio.SubprocessFlags.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 Gio.SubprocessFlags.STDOUT_PIPE, stdout_buf will contain the data read from stdout. Otherwise, for subprocesses not created with Gio.SubprocessFlags.STDOUT_PIPE, stdout_buf will be set to None. Similar provisions apply to stderr_buf and Gio.SubprocessFlags.STDERR_PIPE.

As usual, any output variable may be given as None to ignore it.

If you desire the stdout and stderr data to be interleaved, create the subprocess with Gio.SubprocessFlags.STDOUT_PIPE and Gio.SubprocessFlags.STDERR_MERGE. The merged result will be returned in stdout_buf and stderr_buf will be set to None.

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: Gio.Subprocess.get_if_exited(), Gio.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).

New in version 2.40.

communicate_async(stdin_buf, cancellable, callback, *user_data)[source]¶

Parameters:

stdin_buf (GLib.Bytes or None) – Input data, or None
cancellable (Gio.Cancellable or None) – Cancellable
callback (Gio.AsyncReadyCallback or None) – Callback
user_data (object or None) – User data

Asynchronous version of Gio.Subprocess.communicate(). Complete invocation with Gio.Subprocess.communicate_finish().

communicate_finish(result)[source]¶

Parameters:

result (Gio.AsyncResult) – Result

Raises:

GLib.Error

Returns:

stdout_buf:: Return location for stdout data
stderr_buf:: Return location for stderr data

Return type:

(bool, stdout_buf: GLib.Bytes or None, stderr_buf: GLib.Bytes or None)

Complete an invocation of Gio.Subprocess.communicate_async().

communicate_utf8(stdin_buf, cancellable)[source]¶

Parameters:

stdin_buf (str or None) – data to send to the stdin of the subprocess, or None
cancellable (Gio.Cancellable or None) – a Gio.Cancellable

Raises:

GLib.Error

Returns:

stdout_buf:: data read from the subprocess stdout
stderr_buf:: data read from the subprocess stderr

Return type:

(bool, stdout_buf: str or None, stderr_buf: str or None)

Like Gio.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.

communicate_utf8_async(stdin_buf, cancellable, callback, *user_data)[source]¶

Parameters:

stdin_buf (str or None) – Input data, or None
cancellable (Gio.Cancellable or None) – Cancellable
callback (Gio.AsyncReadyCallback or None) – Callback
user_data (object or None) – User data

Asynchronous version of Gio.Subprocess.communicate_utf8(). Complete invocation with Gio.Subprocess.communicate_utf8_finish().

communicate_utf8_finish(result)[source]¶

Parameters:

result (Gio.AsyncResult) – Result

Raises:

GLib.Error

Returns:

stdout_buf:: Return location for stdout data
stderr_buf:: Return location for stderr data

Return type:

(bool, stdout_buf: str or None, stderr_buf: str or None)

Complete an invocation of Gio.Subprocess.communicate_utf8_async().

force_exit()[source]¶

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 Gio.Subprocess.wait() to monitor the status of the process after calling this function.

On Unix, this function sends %SIGKILL.

New in version 2.40.

get_exit_status()[source]¶

Returns:: the exit status
Return type:: int

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 Gio.Subprocess.wait() and unless Gio.Subprocess.get_if_exited() returned True.

New in version 2.40.

get_identifier()[source]¶

Returns:: the subprocess identifier, or None if the subprocess has terminated
Return type:: str or None

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 None.

New in version 2.40.

get_if_exited()[source]¶

Returns:: True if the case of a normal exit
Return type:: bool

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 Gio.Subprocess.wait() has returned.

New in version 2.40.

get_if_signaled()[source]¶

Returns:: True if the case of termination due to a signal
Return type:: bool

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 Gio.Subprocess.wait() has returned.

New in version 2.40.

get_status()[source]¶

Returns:: the (meaningless) waitpid() exit status from the kernel
Return type:: int

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 GLib.spawn_check_wait_status().

It is more likely that you want to use Gio.Subprocess.get_if_exited() followed by Gio.Subprocess.get_exit_status().

It is an error to call this function before Gio.Subprocess.wait() has returned.

New in version 2.40.

get_stderr_pipe()[source]¶

Returns:: the stderr pipe
Return type:: Gio.InputStream or None

Gets the Gio.InputStream from which to read the stderr output of self.

The process must have been created with Gio.SubprocessFlags.STDERR_PIPE, otherwise None will be returned.

New in version 2.40.

get_stdin_pipe()[source]¶

Returns:: the stdout pipe
Return type:: Gio.OutputStream or None

Gets the Gio.OutputStream that you can write to in order to give data to the stdin of self.

The process must have been created with Gio.SubprocessFlags.STDIN_PIPE and not Gio.SubprocessFlags.STDIN_INHERIT, otherwise None will be returned.

New in version 2.40.

get_stdout_pipe()[source]¶

Returns:: the stdout pipe
Return type:: Gio.InputStream or None

Gets the Gio.InputStream from which to read the stdout output of self.

The process must have been created with Gio.SubprocessFlags.STDOUT_PIPE, otherwise None will be returned.

New in version 2.40.

get_successful()[source]¶

Returns:: True if the process exited cleanly with a exit status of 0
Return type:: bool

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 Gio.Subprocess.wait() has returned.

New in version 2.40.

get_term_sig()[source]¶

Returns:: the signal causing termination
Return type:: int

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 Gio.Subprocess.wait() and unless Gio.Subprocess.get_if_signaled() returned True.

New in version 2.40.

send_signal(signal_num)[source]¶

Parameters:: signal_num (int) – the signal number to send

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.

New in version 2.40.

wait(cancellable)[source]¶

Parameters:: cancellable (Gio.Cancellable or None) – a Gio.Cancellable
Raises:: GLib.Error
Returns:: True on success, False if cancellable was cancelled
Return type:: bool

Synchronously wait for the subprocess to terminate.

After the process terminates you can query its exit status with functions such as Gio.Subprocess.get_if_exited() and Gio.Subprocess.get_exit_status().

This function does not fail in the case of the subprocess having abnormal termination. See Gio.Subprocess.wait_check() for that.

Cancelling cancellable doesn’t kill the subprocess. Call Gio.Subprocess.force_exit() if it is desirable.

New in version 2.40.

wait_async(cancellable, callback, *user_data)[source]¶

Parameters:

cancellable (Gio.Cancellable or None) – a Gio.Cancellable, or None
callback (Gio.AsyncReadyCallback or None) – a Gio.AsyncReadyCallback to call when the operation is complete
user_data (object or None) – user_data for callback

Wait for the subprocess to terminate.

This is the asynchronous version of Gio.Subprocess.wait().

New in version 2.40.

wait_check(cancellable)[source]¶

Parameters:: cancellable (Gio.Cancellable or None) – a Gio.Cancellable
Raises:: GLib.Error
Returns:: True on success, False if process exited abnormally, or cancellable was cancelled
Return type:: bool

Combines Gio.Subprocess.wait() with GLib.spawn_check_wait_status().

New in version 2.40.

wait_check_async(cancellable, callback, *user_data)[source]¶

Parameters:

cancellable (Gio.Cancellable or None) – a Gio.Cancellable, or None
callback (Gio.AsyncReadyCallback or None) – a Gio.AsyncReadyCallback to call when the operation is complete
user_data (object or None) – user_data for callback

Combines Gio.Subprocess.wait_async() with GLib.spawn_check_wait_status().

This is the asynchronous version of Gio.Subprocess.wait_check().

New in version 2.40.

wait_check_finish(result)[source]¶

Parameters:: result (Gio.AsyncResult) – the Gio.AsyncResult passed to your Gio.AsyncReadyCallback
Raises:: GLib.Error
Returns:: True if successful, or False with error set
Return type:: bool

Collects the result of a previous call to Gio.Subprocess.wait_check_async().

New in version 2.40.

wait_finish(result)[source]¶

Parameters:: result (Gio.AsyncResult) – the Gio.AsyncResult passed to your Gio.AsyncReadyCallback
Raises:: GLib.Error
Returns:: True if successful, or False with error set
Return type:: bool

Collects the result of a previous call to Gio.Subprocess.wait_async().

New in version 2.40.

Property Details¶

Gio.Subprocess.props.argv¶

Name:: argv
Type:: [str]
Default Value:: []
Flags:: WRITABLE, CONSTRUCT_ONLY

Argument vector.

New in version 2.40.

Gio.Subprocess.props.flags¶

Name:: flags
Type:: Gio.SubprocessFlags
Default Value:: Gio.SubprocessFlags.NONE
Flags:: WRITABLE, CONSTRUCT_ONLY

Subprocess flags.

New in version 2.40.