class Gio::Subprocess
- Gio::Subprocess
- GObject::Object
- Reference
- Object
Overview
#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 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. 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).
Included Modules
Defined in:
lib/gi-crystal/src/auto/gio-2.0/subprocess.crConstructors
-
.new(argv : Enumerable(String), flags : Gio::SubprocessFlags) : self
Create a new process with the given flags and varargs argument list.
-
.new
Initialize a new
Subprocess. - .new(*, argv : Enumerable(String) | Nil = nil, flags : Gio::SubprocessFlags | Nil = nil)
Class Method Summary
-
.g_type : UInt64
Returns the type id (GType) registered in GLib type system.
Instance Method Summary
-
#==(other : self)
Returns
trueif this reference is the same as other. - #argv=(value : Enumerable(String)) : Enumerable(String)
-
#communicate(stdin_buf : GLib::Bytes | Nil, cancellable : Gio::Cancellable | Nil) : Bool
Communicate with the subprocess until it terminates, and all input and output has been completed.
-
#communicate_async(stdin_buf : GLib::Bytes | Nil, cancellable : Gio::Cancellable | Nil, callback : Gio::AsyncReadyCallback | Nil, user_data : Pointer(Void) | Nil) : Nil
Asynchronous version of g_subprocess_communicate().
-
#communicate_finish(result : Gio::AsyncResult) : Bool
Complete an invocation of g_subprocess_communicate_async().
-
#communicate_utf8(stdin_buf : String | Nil, cancellable : Gio::Cancellable | Nil) : Bool
Like g_subprocess_communicate(), but validates the output of the process as UTF-8, and returns it as a regular NUL terminated string.
-
#communicate_utf8_async(stdin_buf : String | Nil, cancellable : Gio::Cancellable | Nil, callback : Gio::AsyncReadyCallback | Nil, user_data : Pointer(Void) | Nil) : Nil
Asynchronous version of g_subprocess_communicate_utf8().
-
#communicate_utf8_finish(result : Gio::AsyncResult) : Bool
Complete an invocation of g_subprocess_communicate_utf8_async().
-
#exit_status : Int32
Check the exit status of the subprocess, given that it exited normally.
- #flags=(value : Gio::SubprocessFlags) : Gio::SubprocessFlags
-
#force_exit : Nil
Use an operating-system specific method to attempt an immediate, forceful termination of the process.
-
#hash(hasher)
See
Object#hash(hasher) -
#identifier : String | Nil
On UNIX, returns the process ID as a decimal string.
-
#if_exited : Bool
Check if the given subprocess exited normally (ie: by way of exit() or return from main()).
-
#if_signaled : Bool
Check if the given subprocess terminated in response to a signal.
-
#send_signal(signal_num : Int32) : Nil
Sends the UNIX signal signal_num to the subprocess, if it is still running.
-
#status : Int32
Gets the raw status code of the process, as from waitpid().
-
#stderr_pipe : Gio::InputStream | Nil
Gets the #GInputStream from which to read the stderr output of subprocess.
-
#stdin_pipe : Gio::OutputStream | Nil
Gets the #GOutputStream that you can write to in order to give data to the stdin of subprocess.
-
#stdout_pipe : Gio::InputStream | Nil
Gets the #GInputStream from which to read the stdout output of subprocess.
-
#successful : Bool
Checks if the process was "successful".
-
#term_sig : Int32
Get the signal number that caused the subprocess to terminate, given that it terminated due to a signal.
-
#wait(cancellable : Gio::Cancellable | Nil) : Bool
Synchronously wait for the subprocess to terminate.
-
#wait_async(cancellable : Gio::Cancellable | Nil, callback : Gio::AsyncReadyCallback | Nil, user_data : Pointer(Void) | Nil) : Nil
Wait for the subprocess to terminate.
-
#wait_check(cancellable : Gio::Cancellable | Nil) : Bool
Combines g_subprocess_wait() with g_spawn_check_wait_status().
-
#wait_check_async(cancellable : Gio::Cancellable | Nil, callback : Gio::AsyncReadyCallback | Nil, user_data : Pointer(Void) | Nil) : Nil
Combines g_subprocess_wait_async() with g_spawn_check_wait_status().
-
#wait_check_finish(result : Gio::AsyncResult) : Bool
Collects the result of a previous call to g_subprocess_wait_check_async().
-
#wait_finish(result : Gio::AsyncResult) : Bool
Collects the result of a previous call to g_subprocess_wait_async().
Instance methods inherited from module Gio::Initable
init(cancellable : Gio::Cancellable | Nil) : Bool
init,
newv(object_type : UInt64, parameters : Enumerable(GObject::Parameter), cancellable : Gio::Cancellable | Nil) : GObject::Object
newv,
to_unsafe
to_unsafe
Constructor methods inherited from module Gio::Initable
cast(obj : GObject::Object) : self
cast
Class methods inherited from module Gio::Initable
cast?(obj : GObject::Object) : self | Nil
cast?,
g_type : UInt64
g_type
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
Macros inherited from class GObject::Object
previous_vfunc(*args)
previous_vfunc,
previous_vfunc!(*args)
previous_vfunc!,
signal(signature)
signal
Constructor Detail
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.
The argument list must be terminated with nil.
Class Method Detail
Returns the type id (GType) registered in GLib type system.
Instance Method Detail
Returns true if this reference is the same as other. Invokes same?.
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 nil. Similar provisions apply to stderr_buf and %G_SUBPROCESS_FLAGS_STDERR_PIPE.
As usual, any output variable may be given as nil 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 nil.
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).
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.
On error, stdout_buf and stderr_buf will be set to undefined values and should not be used.
Asynchronous version of g_subprocess_communicate_utf8(). Complete invocation with g_subprocess_communicate_utf8_finish().
Complete an invocation of g_subprocess_communicate_utf8_async().
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.
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.
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 nil.
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.
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.
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 nil 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 nil 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 nil 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.
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.
Wait for the subprocess to terminate.
This is the asynchronous version of g_subprocess_wait().
Combines g_subprocess_wait() with g_spawn_check_wait_status().
Combines g_subprocess_wait_async() with g_spawn_check_wait_status().
This is the asynchronous version of g_subprocess_wait_check().
Collects the result of a previous call to g_subprocess_wait_check_async().
Collects the result of a previous call to g_subprocess_wait_async().