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$one = 123;$one++;$two = time();$pid = [];$pid = pcntl_fork();$three = time();When: pcntl_fork() function is executed, a child process will be created. The child process will copy everything about the current process, that is, the parent process: data, code, and state.
1. When pcntl_fork() successfully creates a child process, the child process number is returned in the parent process, 0 is returned in the child process, and -1 is returned if it fails2 .The child process will copy the code and data of the parent process. Then it means: the code and data owned by the child and parent processes will be exactly the same. 3.Key points: The child process will copy the status of the parent process, then there is the above sample code: In the fifth line, pcntl_fork is executed, then The code of the created subprocess is also executed from the fifth line. The child process copied the data and code. Therefore, the same exists in the child process: $one, $two and other variables
for ($i = 0; $i < 3; $i++) {
$pid = pcntl_fork();}sleep(30);
那么：上面的for循环，实际会产生多少个子进程？答案是7个，在linux下，用ps命令将可以看到8个进程（1个父进程，7个子进程）
Reason: The parent process is at
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