(PHP 8 >= 8.4.0)
pcntl_waitid — Waits for a child process to change state
Obtains status information pertaining to termination, stop, and/or continue events in one of the caller's child processes.
Unless WNOHANG flag is passed, the calling process will
become blocked until an error occurs, or status information becomes
available that satisfies all of the following:
idtype and
id arguments.
flags argument.
If matching status information is available prior to the call to pcntl_waitid(), return shall be immediate. If matching status information is available for two or more child processes, the order in which their status is reported is unspecified.
注意:
This documentation covers the POSIX specification of the
waitidfunction, along with some additional parameters specific to implementations on Linux, NetBSD and FreeBSD. Please see your system'swaitid(2)man page for specific details as to howwaitidworks on your system.
idtypeididtype and id arguments
are used to specify which children to wait for.
If idtype is P_ALL |
wait for any child process, id is ignored.
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If idtype is P_PID |
wait for the child with process ID equal to id.
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If idtype is P_PGID |
wait for any child with process group ID equal to id.
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If idtype is P_PIDFD (since Linux 5.4) |
wait for the child referred to by the PID file descriptor specified in
id.
(See the Linux pidfd_open(2) man page for further
information on PID file descriptors.)
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If idtype is P_UID
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wait for processes whose effective user ID is equal to
id.
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If idtype is P_GID
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wait for processes whose effective group ID is equal to
id.
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If idtype is P_SID
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wait for processes whose session ID is equal to
id.
If the child process started its own session, its session ID will be
the same as its process ID. Otherwise the session ID of a child
process will match the caller's session ID.
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If idtype is P_JAILID
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wait for processes within a jail whose jail identifier is equal to
id.
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info
The info parameter is set to an array
containing information about the signal.
info array may contain the following keys:
signo: Signal numbererrno: System error numbercode: Signal codestatus: Exit value or signalpid: Sending process IDuid: Real user ID of sending processutime: User time consumedstime: System time consumedflags
The value of flags is the value of zero or more of
the following constants OR'ed together:
WCONTINUED |
Status shall be returned for any continued child process whose
status either has not been reported since it continued from a job
control stop or has been reported only by calls to
pcntl_waitid() with the
WNOWAIT flag set.
|
WEXITED |
Wait for processes that have exited. |
WNOHANG |
Do not hang if no status is available; return immediately. |
WNOWAIT |
Keep the process whose status is returned in
info in a waitable state. This shall not
affect the state of the process; the process may be waited for again
after this call completes.
|
WSTOPPED |
Status shall be returned for any child that has stopped upon receipt
of a signal, and whose status either has not been reported since it
stopped or has been reported only by calls to
pcntl_waitid() with the
WNOWAIT flag set.
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pcntl_waitid() returns true if
WNOHANG was specified and status is not available for
any process specified by idtype and
id.
pcntl_waitid() returns true due to the change of state
of one of its children.
Otherwise, false is returned and pcntl_get_last_error()
can be used to get the errno error number.
注意:
Once an
errnoerror number has been obtained, pcntl_strerror() can be used to get the text message associated with it.
ECHILD |
The calling process has no existing unwaited-for child processes. |
EINTR |
pcntl_waitid() was interrupted by a signal. |
EINVAL |
An invalid value was specified for flags, or
idtype and id specify an
invalid set of processes.
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