The pcntl_wait function fails to suspend the parent class process

Why won’t the parent process be suspended when

sum =2?

$sum = 0;

<code>    while(true){
        $sum++;
        $pid= pcntl_fork();

        switch($pid){

            case "-1":

                echo"couldn't fork";

                break;
            case "0":{

                var_dump(getmypid());
                var_dump(pcntl_wifexited($status), pcntl_wifstopped($status), pcntl_wifsignaled($status), pcntl_wexitstatus($status), pcntl_wtermsig($status));
                echo 'ppppppppp';
</code>

<code>                exit(0);
            }

            default: {
                if($sum == 2){

                   // $subPid = pcntl_waitpid(-1, $status, SI_ASYNCIO);
                   $subPid = pcntl_wait($status);
                    echo '挂起'."\n";
                }

                var_dump('主'.getmypid());
                var_dump($subPid);
                echo "I'm child" . getmypid() . "\n";
                echo 'ccp';
                //就会执行子进程
                sleep(30);
                echo "\n\n\n";
            }

              //  exit(0);

        }
        var_dump(getmypid());
        echo 'iiiiiii';
        if($sum == 2)
        break;

    }
    
    
    这个是答案 
                    string(8) "主26003"</code>

NULL

I'm child26003
ccpint(26004)
bool(true)
bool(false)
bool(false)
int(0)
int(0)
pppppppppp

int(26003)

iiiiiii hangs
string(8) "main 26003"
int(26004)
I'm child26003
ccpint(26005)
bool(true)
bool(false)
bool(false)
int (0)
int(0)
ppppppppp

int(26003)

iiiiiii

Reply content:

Why won’t the parent process be suspended when

sum =2?

$sum = 0;

<code>    while(true){
        $sum++;
        $pid= pcntl_fork();

        switch($pid){

            case "-1":

                echo"couldn't fork";

                break;
            case "0":{

                var_dump(getmypid());
                var_dump(pcntl_wifexited($status), pcntl_wifstopped($status), pcntl_wifsignaled($status), pcntl_wexitstatus($status), pcntl_wtermsig($status));
                echo 'ppppppppp';
</code>

<code>                exit(0);
            }

            default: {
                if($sum == 2){

                   // $subPid = pcntl_waitpid(-1, $status, SI_ASYNCIO);
                   $subPid = pcntl_wait($status);
                    echo '挂起'."\n";
                }

                var_dump('主'.getmypid());
                var_dump($subPid);
                echo "I'm child" . getmypid() . "\n";
                echo 'ccp';
                //就会执行子进程
                sleep(30);
                echo "\n\n\n";
            }

              //  exit(0);

        }
        var_dump(getmypid());
        echo 'iiiiiii';
        if($sum == 2)
        break;

    }
    
    
    这个是答案 
                    string(8) "主26003"</code>

NULL

I'm child26003

ccpint(26004)
bool(true)
bool(false)
bool(false)
int(0)
int(0)
pppppppppp

int(26003)

iiiiiii hangs

string(8) "main 26003"
int(26004)
I'm child26003
ccpint(26005)
bool(true)
bool(false)
bool(false)
int (0)
int(0)
ppppppppp

int(26003)

iiiiiii