如果perl -cw发出警告,则设置退出状态

use warnings;
asd;

Unquoted String "asd" may clash ...
USELEss use of a constant in void context ...
a.pm syntax OK

在BEGIN块中设置警告处理程序(靠近脚本顶部,因此在可能触发编译时警告的代码之前解析此块),并在ENDchecK块中调整退出状态.

use Strict;
use warnings;
my $warnings;
BEGIN {
    $SIG{__WARN__} = sub { $warnings++; CORE::warn @_ }
}
$used::only::once = 42;
checK {
    if ($^C && $warnings > 0) {
        exit $warnings;
    }
}

当且仅当您使用-c选项调用perl时,$^C变量才为真.