pcntl_wait
(PHP 5, PHP 7)
pcntl_wait — Waits on or returns the status of a forked child
Description
pcntl_wait ( int &$status [, int $options = 0 [, array &$rusage ]] ) : int
The wait function suspends execution of the current process until a child has exited, or until a signal is delivered whose action is to terminate the current process or to call a signal handling function. If a child has already exited by the time of the call (a so-called "zombie" process), the function returns immediately. Any system resources used by the child are freed. Please see your system's wait(2) man page for specific details as to how wait works on your system.
Note:
This function is equivalent to calling pcntl_waitpid() with a
-1pidand nooptions.
Parameters
-
status -
pcntl_wait() will store status information in the
statusparameter which can be evaluated using the following functions: pcntl_wifexited(), pcntl_wifstopped(), pcntl_wifsignaled(), pcntl_wexitstatus(), pcntl_wtermsig() and pcntl_wstopsig(). -
options -
If wait3 is available on your system (mostly BSD-style systems), you can provide the optional
optionsparameter. If this parameter is not provided, wait will be used for the system call. If wait3 is not available, providing a value foroptionswill have no effect. The value ofoptionsis the value of zero or more of the following two constantsOR'ed together:Possible values for optionsWNOHANGReturn immediately if no child has exited. WUNTRACEDReturn for children which are stopped, and whose status has not been reported.
Return Values
pcntl_wait() returns the process ID of the child which exited, -1 on error or zero if WNOHANG was provided as an option (on wait3-available systems) and no child was available.
See Also
- pcntl_fork() - Forks the currently running process
- pcntl_signal() - Installs a signal handler
- pcntl_wifexited() - Checks if status code represents a normal exit
- pcntl_wifstopped() - Checks whether the child process is currently stopped
- pcntl_wifsignaled() - Checks whether the status code represents a termination due to a signal
- pcntl_wexitstatus() - Returns the return code of a terminated child
- pcntl_wtermsig() - Returns the signal which caused the child to terminate
- pcntl_wstopsig() - Returns the signal which caused the child to stop
- pcntl_waitpid() - Waits on or returns the status of a forked child
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https://www.php.net/manual/en/function.pcntl-wait.php