perl多进程主进程等子进程结束

将“use POSIX ":sys_wait_h";”去掉，还有在主进程中打印子进程中的变量是不对的，主进程不知道子进程的状况，除非你用pipe将变量值传给主进程，
##################################################
#!/usr/bin/perl
#use POSIX ":sys_wait_h";
my $a=10;
for($i=1;$i<=3;$i++){
my $pid=fork();
if (!defined($pid)) {
print "Error in fork: $!";
exit 1;
}
if ($pid == 0 ) {
if($i==1){
sleep(9);
$b1=$a+1;
print "$b1\t";
exit 0;}
elsif($i==2){
sleep(5);
$b2=$a+10;
print "$b2\t";
exit 0;}
else{
sleep(3);
$b3=$a+100;
print "$b3\t";
exit 0; }
}
}
print "~~~~~~~~~~split~~~~~~~~~~~\n";
while (($collect = waitpid(-1, WNOHANG)) > 0) {
1;
}

##################### 输出 ##########
bsd2# perl test.pl
~~~~~~~~~~split~~~~~~~~~~~
110     20      11      bsd2#