Syntax
int
pcntl_wait ( int &status [, int options] )
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.
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.
If wait3 is available on your system (mostly BSD-style systems), you can
provide the optional options parameter. If this
parameter is not provided, wait will be used for the system call. If
wait3 is not available, providing a value for options
will have no effect. The value of options
is the value of zero or more of the following two constants
OR'ed together:
Table 1. Possible values for options if wait3 is available
| WNOHANG |
Return immediately if no child has exited.
|
| WUNTRACED |
Return for children which are stopped, and whose status has
not been reported.
|
pcntl_wait() will store status information
in the status parameter which can be
evaluated using the following functions:
pcntl_wifexited(),
pcntl_wifstopped(),
pcntl_wifsignaled(),
pcntl_wexitstatus(),
pcntl_wtermsig() and
pcntl_wstopsig().
Note:
This function is equivalent to calling pcntl_waitpid()
with a -1 pid and no
options.
See also pcntl_fork(),
pcntl_signal(),
pcntl_wifexited(),
pcntl_wifstopped(),
pcntl_wifsignaled(),
pcntl_wexitstatus(),
pcntl_wtermsig(),
pcntl_wstopsig() and
pcntl_waitpid().