Enum nix::sys::wait::WaitStatus

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pub enum WaitStatus {
    Exited(Pid, i32),
    Signaled(Pid, Signal, bool),
    Stopped(Pid, Signal),
    PtraceEvent(Pid, Signal, c_int),
    PtraceSyscall(Pid),
    Continued(Pid),
    StillAlive,
}
Expand description

Possible return values from wait() or waitpid().

Each status (other than StillAlive) describes a state transition in a child process Pid, such as the process exiting or stopping, plus additional data about the transition if any.

Note that there are two Linux-specific enum variants, PtraceEvent and PtraceSyscall. Portable code should avoid exhaustively matching on WaitStatus.

Variants§

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Exited(Pid, i32)

The process exited normally (as with exit() or returning from main) with the given exit code. This case matches the C macro WIFEXITED(status); the second field is WEXITSTATUS(status).

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Signaled(Pid, Signal, bool)

The process was killed by the given signal. The third field indicates whether the signal generated a core dump. This case matches the C macro WIFSIGNALED(status); the last two fields correspond to WTERMSIG(status) and WCOREDUMP(status).

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Stopped(Pid, Signal)

The process is alive, but was stopped by the given signal. This is only reported if WaitPidFlag::WUNTRACED was passed. This case matches the C macro WIFSTOPPED(status); the second field is WSTOPSIG(status).

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PtraceEvent(Pid, Signal, c_int)

The traced process was stopped by a PTRACE_EVENT_* event. See nix::sys::ptrace and ptrace(2) for more information. All currently-defined events use SIGTRAP as the signal; the third field is the PTRACE_EVENT_* value of the event.

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PtraceSyscall(Pid)

The traced process was stopped by execution of a system call, and PTRACE_O_TRACESYSGOOD is in effect. See ptrace(2) for more information.

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Continued(Pid)

The process was previously stopped but has resumed execution after receiving a SIGCONT signal. This is only reported if WaitPidFlag::WCONTINUED was passed. This case matches the C macro WIFCONTINUED(status).

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StillAlive

There are currently no state changes to report in any awaited child process. This is only returned if WaitPidFlag::WNOHANG was used (otherwise wait() or waitpid() would block until there was something to report).

Implementations§

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impl WaitStatus

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pub fn pid(&self) -> Option<Pid>

Extracts the PID from the WaitStatus unless it equals StillAlive.

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impl WaitStatus

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pub fn from_raw(pid: Pid, status: i32) -> Result<WaitStatus>

Convert a raw wstatus as returned by waitpid/wait into a WaitStatus

Errors

Returns an Error corresponding to EINVAL for invalid status values.

Examples

Convert a wstatus obtained from libc::waitpid into a WaitStatus:

use nix::sys::wait::WaitStatus;
use nix::sys::signal::Signal;
let pid = nix::unistd::Pid::from_raw(1);
let status = WaitStatus::from_raw(pid, 0x0002);
assert_eq!(status, Ok(WaitStatus::Signaled(pid, Signal::SIGINT, false)));

Trait Implementations§

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impl Clone for WaitStatus

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fn clone(&self) -> WaitStatus

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for WaitStatus

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

Formats the value using the given formatter. Read more
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impl Hash for WaitStatus

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fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl PartialEq for WaitStatus

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fn eq(&self, other: &WaitStatus) -> bool

This method tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl Copy for WaitStatus

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impl Eq for WaitStatus

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impl StructuralEq for WaitStatus

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impl StructuralPartialEq for WaitStatus

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.