Enum `WaitStatus`

pub enum WaitStatus

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`

fn pid(&self) -> Option<Pid>: Extracts the PID from the WaitStatus unless it equals StillAlive.

`impl WaitStatus`

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)));