class Gio::SubprocessLauncher

Overview

This class contains a set of options for launching child processes, such as where its standard input and output will be directed, the argument list, the environment, and more.

While the #GSubprocess class has high level functions covering popular cases, use of this class allows access to more advanced options. It can also be used to launch multiple subprocesses with a similar configuration.

Defined in:

lib/gi-crystal/src/auto/gio-2.0/subprocess_launcher.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(flags : Gio::SubprocessFlags) : self #

Creates a new #GSubprocessLauncher.

The launcher is created with the default options. A copy of the environment of the calling process is made at the time of this call and will be used as the environment that the process is launched in.


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def self.new #

Initialize a new SubprocessLauncher.


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def self.new(*, flags : Gio::SubprocessFlags | 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 close : Nil #

Closes all the file descriptors previously passed to the object with g_subprocess_launcher_take_fd(), g_subprocess_launcher_take_stderr_fd(), etc.

After calling this method, any subsequent calls to g_subprocess_launcher_spawn() or g_subprocess_launcher_spawnv() will return %G_IO_ERROR_CLOSED. This method is idempotent if called more than once.

This function is called automatically when the #GSubprocessLauncher is disposed, but is provided separately so that garbage collected language bindings can call it earlier to guarantee when FDs are closed.


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def cwd=(cwd : String) : Nil #

Sets the current working directory that processes will be launched with.

By default processes are launched with the current working directory of the launching process at the time of launch.


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def environ=(env : Enumerable(String)) : Nil #

Replace the entire environment of processes launched from this launcher with the given 'environ' variable.

Typically you will build this variable by using g_listenv() to copy the process 'environ' and using the functions g_environ_setenv(), g_environ_unsetenv(), etc.

As an alternative, you can use g_subprocess_launcher_setenv(), g_subprocess_launcher_unsetenv(), etc.

Pass an empty array to set an empty environment. Pass nil to inherit the parent process’ environment. As of GLib 2.54, the parent process’ environment will be copied when g_subprocess_launcher_set_environ() is called. Previously, it was copied when the subprocess was executed. This means the copied environment may now be modified (using g_subprocess_launcher_setenv(), etc.) before launching the subprocess.

On UNIX, all strings in this array can be arbitrary byte strings. On Windows, they should be in UTF-8.


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def flags=(flags : Gio::SubprocessFlags) : Nil #

Sets the flags on the launcher.

The default flags are %G_SUBPROCESS_FLAGS_NONE.

You may not set flags that specify conflicting options for how to handle a particular stdio stream (eg: specifying both %G_SUBPROCESS_FLAGS_STDIN_PIPE and %G_SUBPROCESS_FLAGS_STDIN_INHERIT).

You may also not set a flag that conflicts with a previous call to a function like g_subprocess_launcher_set_stdin_file_path() or g_subprocess_launcher_take_stdout_fd().


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def getenv(variable : String) : Path | Nil #

Returns the value of the environment variable variable in the environment of processes launched from this launcher.

On UNIX, the returned string can be an arbitrary byte string. On Windows, it will be UTF-8.


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def hash(hasher) #
Description copied from class Reference

See Object#hash(hasher)


def setenv(variable : String, value : String, overwrite : Bool) : Nil #

Sets the environment variable variable in the environment of processes launched from this launcher.

On UNIX, both the variable's name and value can be arbitrary byte strings, except that the variable's name cannot contain '='. On Windows, they should be in UTF-8.


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def spawnv(argv : Enumerable(String)) : Gio::Subprocess #

Creates a #GSubprocess given a provided array of arguments.


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def spawnv(*argv : String) #

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def stderr_file_path=(path : String | Nil) : Nil #

Sets the file path to use as the stderr for spawned processes.

If path is nil then any previously given path is unset.

The file will be created or truncated when the process is spawned, as would be the case if using '2>' at the shell.

If you want to send both stdout and stderr to the same file then use %G_SUBPROCESS_FLAGS_STDERR_MERGE.

You may not set a stderr file path if a stderr fd is already set or if the launcher flags contain any flags directing stderr elsewhere.

This feature is only available on UNIX.


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def stdin_file_path=(path : String) : Nil #

Sets the file path to use as the stdin for spawned processes.

If path is nil then any previously given path is unset.

The file must exist or spawning the process will fail.

You may not set a stdin file path if a stdin fd is already set or if the launcher flags contain any flags directing stdin elsewhere.

This feature is only available on UNIX.


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def stdout_file_path=(path : String | Nil) : Nil #

Sets the file path to use as the stdout for spawned processes.

If path is nil then any previously given path is unset.

The file will be created or truncated when the process is spawned, as would be the case if using '>' at the shell.

You may not set a stdout file path if a stdout fd is already set or if the launcher flags contain any flags directing stdout elsewhere.

This feature is only available on UNIX.


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def take_fd(source_fd : Int32, target_fd : Int32) : Nil #

Transfer an arbitrary file descriptor from parent process to the child. This function takes ownership of the source_fd; it will be closed in the parent when self is freed.

By default, all file descriptors from the parent will be closed. This function allows you to create (for example) a custom pipe() or socketpair() before launching the process, and choose the target descriptor in the child.

An example use case is GNUPG, which has a command line argument --passphrase-fd providing a file descriptor number where it expects the passphrase to be written.


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def take_stderr_fd(fd : Int32) : Nil #

Sets the file descriptor to use as the stderr for spawned processes.

If fd is -1 then any previously given fd is unset.

Note that the default behaviour is to pass stderr through to the stderr of the parent process.

The passed fd belongs to the #GSubprocessLauncher. It will be automatically closed when the launcher is finalized. The file descriptor will also be closed on the child side when executing the spawned process.

You may not set a stderr fd if a stderr file path is already set or if the launcher flags contain any flags directing stderr elsewhere.

This feature is only available on UNIX.


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def take_stdin_fd(fd : Int32) : Nil #

Sets the file descriptor to use as the stdin for spawned processes.

If fd is -1 then any previously given fd is unset.

Note that if your intention is to have the stdin of the calling process inherited by the child then %G_SUBPROCESS_FLAGS_STDIN_INHERIT is a better way to go about doing that.

The passed fd is noted but will not be touched in the current process. It is therefore necessary that it be kept open by the caller until the subprocess is spawned. The file descriptor will also not be explicitly closed on the child side, so it must be marked O_CLOEXEC if that's what you want.

You may not set a stdin fd if a stdin file path is already set or if the launcher flags contain any flags directing stdin elsewhere.

This feature is only available on UNIX.


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def take_stdout_fd(fd : Int32) : Nil #

Sets the file descriptor to use as the stdout for spawned processes.

If fd is -1 then any previously given fd is unset.

Note that the default behaviour is to pass stdout through to the stdout of the parent process.

The passed fd is noted but will not be touched in the current process. It is therefore necessary that it be kept open by the caller until the subprocess is spawned. The file descriptor will also not be explicitly closed on the child side, so it must be marked O_CLOEXEC if that's what you want.

You may not set a stdout fd if a stdout file path is already set or if the launcher flags contain any flags directing stdout elsewhere.

This feature is only available on UNIX.


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def unsetenv(variable : String) : Nil #

Removes the environment variable variable from the environment of processes launched from this launcher.

On UNIX, the variable's name can be an arbitrary byte string not containing '='. On Windows, it should be in UTF-8.


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