perl讀寫文件Inappropriate ioctl for device算是perl的一個(gè)bug??

027xiatian

Code:

           use FileHandle;

           $fh = new FileHandle;
           if ($fh->open("< file")) {
               print "info:$!\n"
               print <$fh>;
               $fh->close;
           }

在終端環(huán)境下打開任何文件,$! 都會(huì)是Inappropriate ioctl for device

When Perl opens a file, it checks whether or not the terminal is a TTY (so that it can answer the -T $fh filetest operator) by issuing the TCGETS ioctl against it. If the file is a regular file and not a tty, the ioctl fails and sets errno to ENOTTY (string value: "Inappropriate ioctl for device"). As ysth says, the most common reason for seeing an unexpected value in $! is checking it when it's not valid -- that is, anywhere other than immediately after a syscall failed, so testing the result codes of your operations is critically important.

nuclearxin

"< file"
這個(gè)不就是個(gè)文件名嗎？
不懂