Change meaning of \v, \V, and add \h, \H to match Perl6, add \R to match PCRE and...

[p5sagit/p5-mst-13.2.git] / pod / perlfaq5.pod

diff --git a/pod/perlfaq5.pod b/pod/perlfaq5.pod
index d171522..dd11f66 100644 (file)
--- a/pod/perlfaq5.pod
+++ b/pod/perlfaq5.pod
@@ -1,6 +1,6 @@
 =head1 NAME
 
-perlfaq5 - Files and Formats ($Revision: 7875 $)
+perlfaq5 - Files and Formats ($Revision: 8579 $)
 
 =head1 DESCRIPTION
 
@@ -117,17 +117,25 @@ be sure that you're supposed to do that on every line!
    close $out;
 
 To change only a particular line, the input line number, C<$.>, is
-useful. Use C<next> to skip all lines up to line 5, make a change and
-print the result, then stop further processing with C<last>.
+useful. First read and print the lines up to the one you  want to
+change. Next, read the single line you want to change, change it, and
+print it. After that, read the rest of the lines and print those:
 
-       while( <$in> )
+       while( <$in> )   # print the lines before the change
                {
-               next unless $. == 5;
-               s/\b(perl)\b/Perl/g;
                print $out $_;
-               last;
+               last if $. == 4; # line number before change
                }
 
+       my $line = <$in>;
+       $line =~ s/\b(perl)\b/Perl/g;
+       print $out $line;
+
+       while( <$in> )   # print the rest of the lines
+               {
+               print $out $_;
+               }
+               
 To skip lines, use the looping controls. The C<next> in this example
 skips comment lines, and the C<last> stops all processing once it
 encounters either C<__END__> or C<__DATA__>.
@@ -801,7 +809,7 @@ then that is what you should do.
 
 If you know you are only going to use a system that does correctly
 implement appending (i.e. not Win32) then you can omit the seek() from
-the above code.
+the code in the previous answer.
 
 If you know you are only writing code to run on an OS and filesystem that
 does implement append mode correctly (a local filesystem on a modern
@@ -1160,9 +1168,17 @@ a copied one.
 Error checking, as always, has been left as an exercise for the reader.
 
 =head2 How do I close a file descriptor by number?
-X<file, closing file descriptors>
+X<file, closing file descriptors> X<POSIX> X<close>
+
+If, for some reason, you have a file descriptor instead of a
+filehandle (perhaps you used C<POSIX::open>), you can use the
+C<close()> function from the C<POSIX> module:
 
-This should rarely be necessary, as the Perl close() function is to be
+       use POSIX ();
+       
+       POSIX::close( $fd );
+       
+This should rarely be necessary, as the Perl Cclose()> function is to be
 used for things that Perl opened itself, even if it was a dup of a
 numeric descriptor as with MHCONTEXT above.  But if you really have
 to, you may be able to do this:
@@ -1171,12 +1187,11 @@ to, you may be able to do this:
        $rc = syscall(&SYS_close, $fd + 0);  # must force numeric
        die "can't sysclose $fd: $!" unless $rc == -1;
 
-Or, just use the fdopen(3S) feature of open():
+Or, just use the fdopen(3S) feature of C<open()>:
 
        {
-       local *F;
-       open F, "<&=$fd" or die "Cannot reopen fd=$fd: $!";
-       close F;
+       open my( $fh ), "<&=$fd" or die "Cannot reopen fd=$fd: $!";
+       close $fh;
        }
 
 =head2 Why can't I use "C:\temp\foo" in DOS paths?  Why doesn't `C:\temp\foo.exe` work?
@@ -1265,15 +1280,15 @@ If your array contains lines, just print them:
 
 =head1 REVISION
 
-Revision: $Revision: 7875 $
+Revision: $Revision: 8579 $
 
-Date: $Date: 2006-10-04 22:39:26 +0200 (mer, 04 oct 2006) $
+Date: $Date: 2007-01-14 19:28:09 +0100 (Sun, 14 Jan 2007) $
 
 See L<perlfaq> for source control details and availability.
 
 =head1 AUTHOR AND COPYRIGHT
 
-Copyright (c) 1997-2006 Tom Christiansen, Nathan Torkington, and
+Copyright (c) 1997-2007 Tom Christiansen, Nathan Torkington, and
 other authors as noted. All rights reserved.
 
 This documentation is free; you can redistribute it and/or modify it