Struct SpawnSpec 

pub struct SpawnSpec { /* private fields */ }

Typed spawn description accepted by the blessed process boundary.

Implementations

impl SpawnSpec

pub fn new(program: impl Into<OsString>) -> Self

Create a direct (non-shell) command description.

pub fn from_std_command(command: Command) -> Self

Spawn a caller-built std::process::Command verbatim.

The command keeps everything the declarative builder cannot carry: env_remove scrubs of inherited variables, env_clear, non-Unicode argv, its working directory and any hooks the caller installed. The spec still governs stdio routing (its stream modes replace whatever the command had), process group, niceness, creation flags, the address-space limit, owner-death containment and spawn admission.

Those options are applied with the same launch mapping NativeProcess uses (configure_process_command), not the declarative one, so a command is configured exactly once. Adding arguments, environment, env_clear or a working directory to an override spec is rejected at spawn, because it would be silently ignored. Owner-death containment of an override is refused on Windows until the per-spawn Job Object is expressible here.

The command is consumed by the first successful or failed spawn; a clone of this spec that spawns afterwards gets an error.

pub fn creation_flags(self, flags: Option<u32>) -> Self

Set host creation flags (Windows CREATE_*; ignored elsewhere).

Only valid with Self::from_std_command; the declarative spawn path rejects it rather than dropping it.

pub fn address_space_limit_bytes(self, limit: Option<u64>) -> Self

Cap the child’s address space (Linux RLIMIT_AS; the Windows cap is enforced by the owner’s Job Object, not here).

Only valid with Self::from_std_command; the declarative spawn path rejects it rather than dropping it.

pub fn arg(self, arg: impl Into<OsString>) -> Self

Append one argument without requiring UTF-8.

pub fn current_dir(self, path: impl Into<PathBuf>) -> Self

Set the child working directory.

pub fn env(self, key: impl Into<OsString>, value: impl Into<OsString>) -> Self

Add an environment override.

pub fn clear_env(self, clear: bool) -> Self

Start with an empty inherited environment before applying overrides.

pub fn stdin(self, mode: StreamMode) -> Self

Configure child stdin.

pub fn stdout(self, mode: StreamMode) -> Self

Configure child stdout.

pub fn stderr(self, mode: StreamMode) -> Self

Configure child stderr.

pub fn create_process_group(self, create: bool) -> Self

Put the child in its own process group.

This is what makes a group-wide soft signal addressable at all: PlatformEmergencySignal::terminate_group_soft is a no-op without it, because on POSIX the negative-PID signal would otherwise reach the caller’s own group, and on Windows GenerateConsoleCtrlEvent only routes to children spawned with CREATE_NEW_PROCESS_GROUP. It also detaches the child from the parent’s console Ctrl+C, so it is opt-in.

pub fn kill_when_owner_dies(self, kill: bool) -> Self

Kill this child when the spawning process exits unexpectedly.

Linux uses PR_SET_PDEATHSIG(SIGTERM) plus a pre-exec hard-exit race guard when the parent changed before that signal could be armed. Windows assigns the child to a process-wide kill-on-close Job Object. macOS forks a kqueue supervisor before exec and reports spawn success only after its owner and child watches are registered.

pub fn nice(self, nice: Option<i32>) -> Self

Apply the host’s existing niceness policy at child creation.

On Unix this is the requested setpriority(PRIO_PROCESS) niceness. Windows maps the established niceness bands to process creation priority classes; it is deliberately a coarse host mapping rather than a claim that numeric nice values are portable.

pub fn priority(self, priority: ProcessPriority) -> Self

Select portable scheduling intent at native process creation.

pub fn priority_best_effort(self, priority: ProcessPriority) -> Self

Request portable scheduling intent where host policy permits it.

The current host launch boundary applies this at creation; platforms that reject the requested class retain their native error behavior.

pub fn spawn_admission(self, admission: SpawnAdmission) -> Self

Acquire a caller-owned permit around the native spawn attempt.

pub async fn spawn(self) -> Result<PlatformChild>

Spawn using the canonical asynchronous platform operation.

Trait Implementations

impl Clone for SpawnSpec

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for SpawnSpec

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.