Enum WaitStatus

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

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

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).

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).

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).

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.

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.

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).

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

impl WaitStatus

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

Extracts the PID from the WaitStatus unless it equals StillAlive.

impl WaitStatus

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

impl Clone for WaitStatus

fn clone(&self) -> WaitStatus

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for WaitStatus

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

Formats the value using the given formatter.

impl Hash for WaitStatus

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

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for WaitStatus

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

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for WaitStatus

impl Eq for WaitStatus

impl StructuralPartialEq for WaitStatus