Perl: `die` 在使用 gzip 打开不存在的 gz 文件时不起作用

Question

以下脚本会创建一个名为“input.gz”的 gzip 文件。然后脚本尝试使用 gzip -dc 打开“input.gz”。直观地说，如果提供了错误的输入文件名，则应该触发 die。但是，如以下脚本所示，即使提供了错误的输入文件名(“inputx.gz”)，程序也不会死:

use warnings;
use strict;

system("echo PASS | gzip -c > input.gz");

open(IN,"-|","gzip -dc inputx.gz") || die "can't open input.gz!";

print STDOUT "die statment was not triggered!\n";

close IN;

上面脚本的输出是

die statment was not triggered!
gzip: inputx.gz: No such file or directory

我的问题是:为什么 die 语句没有被触发，即使 gzip 因错误退出？当给出错误的文件名时，如何使 die 语句触发？

Answer 1

它被埋在 perlipc ，但这似乎是相关的(强调):

Be careful to check the return values from both open() and close(). If you're writing to a pipe, you should also trap SIGPIPE. Otherwise, think of what happens when you start up a pipe to a command that doesn't exist: the open() will in all likelihood succeed (it only reflects the fork()'s success), but then your output will fail--spectacularly. Perl can't know whether the command worked, because your command is actually running in a separate process whose exec() might have failed. Therefore, while readers of bogus commands return just a quick EOF, writers to bogus commands will get hit with a signal, which they'd best be prepared to handle.

使用 IO::Uncompress::Gunzip改为读取 gzip 文件。