since: 2.40


final class Gio.Subprocess : GObject.Object
  implements Gio.Initable {
  /* No available fields */

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 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 of 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 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 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).

Available since: 2.40


hierarchy this GSubprocess implements_0 GInitable this--implements_0 ancestor_0 GObject ancestor_0--this





Create a new process with the given flags and varargs argument list. By default, matching the g_spawn_async() defaults, the child’s stdin will be set to the system null device, and stdout/stderr will be inherited from the parent. You can use flags to control this behavior.

since: 2.40


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

since: 2.40

Instance methods


Communicate with the subprocess until it terminates, and all input and output has been completed.

since: 2.40


Asynchronous version of g_subprocess_communicate(). Complete invocation with g_subprocess_communicate_finish().


Complete an invocation of g_subprocess_communicate_async().


Like g_subprocess_communicate(), but validates the output of the process as UTF-8, and returns it as a regular NUL terminated string.


Asynchronous version of g_subprocess_communicate_utf8(). Complete invocation with g_subprocess_communicate_utf8_finish().


Complete an invocation of g_subprocess_communicate_utf8_async().


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.

since: 2.40


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.

since: 2.40


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.

since: 2.40


Check if the given subprocess exited normally (ie: by way of exit() or return from main()).

since: 2.40


Check if the given subprocess terminated in response to a signal.

since: 2.40


Gets the raw status code of the process, as from waitpid().

since: 2.40


Gets the GInputStream from which to read the stderr output of subprocess.

since: 2.40


Gets the GOutputStream that you can write to in order to give data to the stdin of subprocess.

since: 2.40


Gets the GInputStream from which to read the stdout output of subprocess.

since: 2.40


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().

since: 2.40


Get the signal number that caused the subprocess to terminate, given that it terminated due to a signal.

since: 2.40


Sends the UNIX signal signal_num to the subprocess, if it is still running.

since: 2.40


Synchronously wait for the subprocess to terminate.

since: 2.40


Wait for the subprocess to terminate.

since: 2.40


Combines g_subprocess_wait() with g_spawn_check_wait_status().

since: 2.40


Combines g_subprocess_wait_async() with g_spawn_check_wait_status().

since: 2.40


Collects the result of a previous call to g_subprocess_wait_check_async().

since: 2.40


Collects the result of a previous call to g_subprocess_wait_async().

since: 2.40

Methods inherited from GObject (43)

Please see GObject for a full list of methods.

Methods inherited from GInitable (1)

Initializes the object implementing the interface.

since: 2.22


No description available.

No description available.


Signals inherited from GObject (1)

The notify signal is emitted on an object when one of its properties has its value set through g_object_set_property(), g_object_set(), et al.