小编mak*_*mak的帖子

在下面的小代码中，我没有收到行 [09] 和 [18] 的错误或警告。我得到的唯一警告是第 [21] 行：

use strict;                                              # [01]
use warnings FATAL => 'unopened';                        # [02]
                                                         # [03]
open(my $outHandleA, ">outputA.txt") or die ("A: $!\n"); # [04] Opened $outHandleA
print $outHandleA "FILE A\n";                            # [05]
close $outHandleA;                                       # [06] Closed $outHandleA
                                                         # [07]
print $outHandleA;                                       # [08]
print $outHandleA "ABC\n";                               # [09] <---
print $outHandleA;                                       # [10]
print "-----";                                           # [11]
                                                         # [12]
open(OUT, ">outputB.txt") or die ("B: $!\n");            # [13] Opened OUT
print OUT "FILE B\n";                                    # …

下面的 Perl 程序在执行过程中不输出任何错误。有没有办法在执行时引发异常以尝试打印到未声明的句柄？对于下面的情况，未声明的句柄将是STD_ERRand DOES_NOT_EXIST。

use strict;

print STD_ERR        "(UNDECLARED) DOES NOT PRINT\n";
print STDERR         "     (EXIST) DOES PRINT\n";
print DOES_NOT_EXIST "(UNDECLARED) DOES NOT PRINT\n";

虽然上面的代码是为了说明问题而简化的，但我有点浪费了几十分钟试图找出我的实际程序中的问题。在我的实际程序中，我意识到我拼错了要打印的句柄。我想避免这种浪费时间，但use strict;就是不这样做。

执行以下简化代码时：

use strict;                                          # [01]
use warnings FATAL => 'unopened';                    # [02]
                                                     # [03]
my ($inHandle, $outHandle) = (\*STDIN, \*STDOUT);    # [04]
print $outHandle "STDOUT  1\n";                      # [05]
                                                     # [06]
# $outHandle re-assigned to outputA.txt ???          # [07]
open($outHandle, ">outputA.txt") or die ("A: $!\n"); # [08]
print $outHandle "FILE A\n";                         # [09]
print             "STDOUT? 2\n";                     # [10]
print STDOUT      "STDOUT  3\n";                     # [11]
close $outHandle;                                    # [12]
                                                     # [13]
# $outHandle is closed                               # [14]
print STDOUT      "STDOUT  4\n";                     # …