Perl 中文件句柄的内置名称是什么？

Question

perl -f ref 列出的名称中的

None 似乎是文件句柄。下面的代码 returns GLOB，所以看起来 filehandle 在内部映射到或管理为 typeglob。对吗？

open FH, '>', "out.txt";
my $ref = \*FH;
print "ref $ref:", ref $ref, "\n";

文件句柄是否有自己的类型名称？

Answer 1

Does a filehandle have its own type name?

IO.

$ perl -MDevel::Peek -e'Dump(*STDOUT{IO});'
SV = IV(0x3ba7118) at 0x3ba7128
  REFCNT = 1
  FLAGS = (TEMP,ROK)
  RV = 0x3bc4390
  SV = PVIO(0x3bc8668) at 0x3bc4390
    REFCNT = 3
    FLAGS = (OBJECT)
    STASH = 0x3bc3fa0   "IO::File"
    IFP = 0x3bbe180
    OFP = 0x3bbe180
    DIRP = 0x0
    LINES = 0
    PAGE = 0
    PAGE_LEN = 60
    LINES_LEFT = 0
    TOP_GV = 0x0
    FMT_GV = 0x0
    BOTTOM_GV = 0x0
    TYPE = '>'
    FLAGS = 0x0

从技术上讲，一个 IO 对象可以有三个与之关联的句柄：一个输入文件句柄 (IFP)、一个输出文件句柄 (OFP) 和一个目录句柄（例如，使用 opendir、DIRP 创建）。通常，只设置输入和输出句柄之一，或者将它们都设置为同一个句柄。由于单独的文件和目录句柄，执行 open(FOO, ...); opendir(FOO, ...); <FOO>; readdir(FOO); 会很好。

it seems filehandle is internally mapped to or managed as a typeglob. Is that correct?

文件和目录 IO 对象通常都封装在一个 glob 中，是的。但这不是必需的。

$ perl -E'
   my $fh = "STDOUT";     say($fh "$fh");
   my $fh = *STDOUT;      say($fh "$fh");
   my $fh = \*STDOUT;     say($fh "$fh");
   my $fh = *STDOUT{IO};  say($fh "$fh");
'
STDOUT                    # Name
*main::STDOUT             # Glob
GLOB(0x1175a48)           # Reference to a glob. (This is returned by open $fh)
IO::File=IO(0x1175a60)    # Reference to a (blessed) IO.

Perl 中文件句柄的内置名称是什么？

What is a built-in name for a filehandle in Perl?

perl

filehandle