PCNTL 函数
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pcntl_waitpid

(PHP 4 >= 4.1.0, PHP 5)

pcntl_waitpidWaits on or returns the status of a forked child

说明

int pcntl_waitpid ( int $pid , int &$status [, int $options=0 ] )

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.

参数

pid

The value of pid can be one of the following:

possible values for pid
< -1 wait for any child process whose process group ID is equal to the absolute value of pid .
-1 wait for any child process; this is the same behaviour that the wait function exhibits.
0 wait for any child process whose process group ID is equal to that of the calling process.
> 0 wait for the child whose process ID is equal to the value of pid .

Note: Specifying -1 as the pid is equivalent to the functionality pcntl_wait() provides (minus options ).

status

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().

options

The value of options is the value of zero or more of the following two global constants OR'ed together:

possible values for options
WNOHANG return immediately if no child has exited.
WUNTRACED return for children which are stopped, and whose status has not been reported.

返回值

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

参见


PCNTL 函数
php 手册 | 脚本学堂 | 脚本编程 | 网站编程 | 系统管理 | 服务器配置 | 数据库管理 | Php教程 | python教程 | 正则表达式 | 批处理脚本 | Centos教程 | Linux基础教程