如何将分叉子进程中的 croak 抛出的异常传播到父进程/前台进程？
在分叉子进程中通过 croak 抛出异常似乎会像后台进程一样打印错误。也就是说，它会破坏 shell 提示符。
如果我die而不是croak，错误消息会作为前台进程弹出。我试图找出 Carp 文档中的原因，但没有成功。
这就是我的意思。 croak 版本：
$ perl Wrapper.pm
$ error: ... does not exist at Wrapper.pm line 624
die 版本：
$ perl Wrapper.pm
error: ... does not exist at Wrapper.pm line 515.
我尝试捕获 fork 并将 $@ 打印到 STDERR 并退出，但这没有效果。有什么想法吗？我希望能够在这种特殊情况下使用 croak 。
尽管我的代码相当复杂，但您可以通过以下方式重现此行为：
$ perl -MCarp -e 'unless (fork) {croak "child"}'
$ child at -e line 1
<- cursor blinking here. Pressing enter gives me a new prompt:
$
$ perl -e 'unless (fork) {die "child"}'
child at -e line 1.
$
已解决： cjm 明白了：
$ perl -e '$SIG{__DIE__} = sub {sleep 1}; unless (fork) {die "child"}'
$ child at -e line 1.
感谢您的帮助！
Throwing an exception via croak in a forked child process seems to print the error as a background process would. That is, it clobbers the shell prompt.
If I die instead of croak, the the error message pops up as a foreground process. I've trying to find out why that is in the Carp documentation without any luck.
Here's what I mean. The croak version:
$ perl Wrapper.pm
$ error: ... does not exist at Wrapper.pm line 624
The die version:
$ perl Wrapper.pm
error: ... does not exist at Wrapper.pm line 515.
I tried trapping the fork and printing $@ to STDERR and exiting, but that didn't have an effect. Any ideas? I'd like to be able to use croak in this particular case.
Although my code is quite a bit more convoluted, here is how you can reproduce this behavior:
$ perl -MCarp -e 'unless (fork) {croak "child"}'
$ child at -e line 1
<- cursor blinking here. Pressing enter gives me a new prompt:
$
$ perl -e 'unless (fork) {die "child"}'
child at -e line 1.
$
Solved: cjm got it:
$ perl -e '$SIG{__DIE__} = sub {sleep 1}; unless (fork) {die "child"}'
$ child at -e line 1.
Thanks for the help!
如果你对这篇内容有疑问，欢迎到本站社区发帖提问 参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。
绑定邮箱获取回复消息
由于您还没有绑定你的真实邮箱，如果其他用户或者作者回复了您的评论，将不能在第一时间通知您！
发布评论
评论（1）
我很确定这只是一个时间问题。
die版本稍快一些，因此它有更好的机会在 shell 打印下一个提示之前输出错误消息。当我尝试运行您的示例时，croak版本通常会在提示之后打印，但有时会在提示之前打印。die版本非常一致地出现在提示之前。I'm pretty sure it's just a timing issue. The
dieversion is slightly faster, so it has a better chance of outputting the error message before the shell can print the next prompt. When I try running your examples, thecroakversion usually gets printed after the prompt, but occasionally it comes before the prompt. Thedieversion pretty consistently comes before the prompt.