The pcntl_waitpid() function
suspends execution of the current process until a child as
specified by the pid
argument 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 as requested by pid 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 waitpid(2) man page for
specific details as to how waitpid works on your system.
pcntl_waitpid() returns the
process ID of the child which exited, -1 on error or zero if
WNOHANG was used and no child was available
The value of pid can
be one of the following:
表格 1. possible values for
pid
pcntl_waitpid() 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().
The value of options
is the value of zero or more of the following two global
constants OR'ed together:
表格 2. possible values for
options
See also pcntl_fork(),
pcntl_signal(),
pcntl_wifexited(),
pcntl_wifstopped(),
pcntl_wifsignaled(),
pcntl_wexitstatus(),
pcntl_wtermsig() and
pcntl_wstopsig().