One of the most common uses for C<open> is one you never
even notice. When you process the ARGV filehandle using
-C<E<lt>ARGVE<gt>>, Perl actually does an implicit open
+C<< <ARGV> >>, Perl actually does an implicit open
on each file in @ARGV. Thus a program called like this:
$ myprogram file1 file2 file3
If @ARGV is empty when the loop first begins, Perl pretends you've opened
up minus, that is, the standard input. In fact, $ARGV, the currently
-open file during C<E<lt>ARGVE<gt>> processing, is even set to "-"
+open file during C<< <ARGV> >> processing, is even set to "-"
in these circumstances.
You are welcome to pre-process your @ARGV before starting the loop to
or die "can't open $pwdinfo: $!";
This sort of thing also comes into play in filter processing. Because
-C<E<lt>ARGVE<gt>> processing employs the normal, shell-style Perl C<open>,
+C<< <ARGV> >> processing employs the normal, shell-style Perl C<open>,
it respects all the special things we've already seen:
$ myprogram f1 "cmd1|" - f2 "cmd2|" f3 < tmpfile
@ARGV = map { m#^\w+://# ? "GET $_ |" : $_ } @ARGV;
-It's not for nothing that this is called magic C<E<lt>ARGVE<gt>>.
+It's not for nothing that this is called magic C<< <ARGV> >>.
Pretty nifty, eh?
=head1 Open E<agrave> la C
O_TRUNC Truncate the file
O_NONBLOCK Non-blocking access
-Less common flags that are sometimes available on some operating systems
-include C<O_BINARY>, C<O_TEXT>, C<O_SHLOCK>, C<O_EXLOCK>, C<O_DEFER>,
-C<O_SYNC>, C<O_ASYNC>, C<O_DSYNC>, C<O_RSYNC>, C<O_NOCTTY>, C<O_NDELAY>
-and C<O_LARGEFILE>. Consult your open(2) manpage or its local equivalent
-for details.
+Less common flags that are sometimes available on some operating
+systems include C<O_BINARY>, C<O_TEXT>, C<O_SHLOCK>, C<O_EXLOCK>,
+C<O_DEFER>, C<O_SYNC>, C<O_ASYNC>, C<O_DSYNC>, C<O_RSYNC>,
+C<O_NOCTTY>, C<O_NDELAY> and C<O_LARGEFILE>. Consult your open(2)
+manpage or its local equivalent for details. (Note: starting from
+Perl release 5.6 the O_LARGEFILE flag, if available, is automatically
+added to the sysopen() flags because large files are the default.)
Here's how to use C<sysopen> to emulate the simple C<open> calls we had
before. We'll omit the C<|| die $!> checks for clarity, but make sure
Sometimes you already have a filehandle open, and want to make another
handle that's a duplicate of the first one. In the shell, we place an
ampersand in front of a file descriptor number when doing redirections.
-For example, C<2E<gt>&1> makes descriptor 2 (that's STDERR in Perl)
+For example, C<< 2>&1 >> makes descriptor 2 (that's STDERR in Perl)
be redirected into descriptor 1 (which is usually Perl's STDOUT).
The same is essentially true in Perl: a filename that begins with an
ampersand is treated instead as a file descriptor if a number, or as a
$fd = $ENV{"MHCONTEXTFD"};
open(MHCONTEXT, "<&=$fd") or die "couldn't fdopen $fd: $!";
-If you're using magic C<E<lt>ARGVE<gt>>, you could even pass in as a
-command line argument in @ARGV something like C<"E<lt>&=$MHCONTEXTFD">,
+If you're using magic C<< <ARGV> >>, you could even pass in as a
+command line argument in @ARGV something like C<"<&=$MHCONTEXTFD">,
but we've never seen anyone actually do this.
=head2 Dispelling the Dweomer
proprietary Macintosh system, which uses a colon where the rest of us
use a slash. Maybe C<sysopen> isn't such a bad idea after all.
-If you want to use C<E<lt>ARGVE<gt>> processing in a totally boring
+If you want to use C<< <ARGV> >> processing in a totally boring
and non-magical way, you could do this first:
# "Sam sat on the ground and put his head in his hands.
it's still easy to get the contents of a document:
use LWP::Simple;
- $doc = get('http://www.sn.no/libwww-perl/');
+ $doc = get('http://www.linpro.no/lwp/');
=head2 Binary Files
projects / p5sagit/p5-mst-13.2.git / blobdiff