golang wait_waitid 代码
文件路径：/src/os/wait_waitid.go
/ Copyright 2016 The Go Authors. All rights reserved.
/ Use of this source code is governed by a BSD-style
/ license that can be found in the LICENSE file.
/ We used to used this code for Darwin, but according to issue #19314
/ waitid returns if the process is stopped, even when using WEXITED.
/go:build linux
package os
import (
"runtime"
"syscall"
"unsafe"
)
const _P_PID = 1
/ blockUntilWaitable attempts to block until a call to p.Wait will
/ succeed immediately, and reports whether it has done so.
/ It does not actually call p.Wait.
func (p *Process) blockUntilWaitable() (bool, error) {
/ The waitid system call expects a pointer to a siginfo_t,
/ which is 128 bytes on all Linux systems.
/ On darwin/amd64, it requires 104 bytes.
/ We don't care about the values it returns.
var siginfo [16]uint64
psig := &siginfo[0]
var e syscall.Errno
for {
_, _, e = syscall.Syscall6(syscall.SYS_WAITID, _P_PID, uintptr(p.Pid), uintptr(unsafe.Pointer(psig)), syscall.WEXITED|syscall.WNOWAIT, 0, 0)
if e != syscall.EINTR {
break
}
}
runtime.KeepAlive(p)
if e != 0 {
/ waitid has been available since Linux 2.6.9, but
/ reportedly is not available in Ubuntu on Windows.
/ See issue 16610.
if e == syscall.ENOSYS {
return false, nil
}
return false, NewSyscallError("waitid", e)
}
return true, nil
}