This section deals with I/O and the "f" issues: filehandles, flushing,
formats, and footers.
-=head2 How do I flush/unbuffer a filehandle? Why must I do this?
+=head2 How do I flush/unbuffer an output filehandle? Why must I do this?
The C standard I/O library (stdio) normally buffers characters sent to
devices. This is done for efficiency reasons, so that there isn't a
Perl, you go though this buffering. syswrite() circumvents stdio and
buffering.
-In most stdio implementations, the type of buffering and the size of
+In most stdio implementations, the type of output buffering and the size of
the buffer varies according to the type of device. Disk files are block
buffered, often with a buffer size of more than 2k. Pipes and sockets
are often buffered with a buffer size between 1/2 and 2k. Serial devices
get the output where you want it when you want it.
If you expect characters to get to your device when you print them there,
-you'll want to autoflush its handle, as in the older:
+you'll want to autoflush its handle.
+Use select() and the C<$|> variable to control autoflushing
+(see L<perlvar/$|> and L<perlfunc/select>):
+
+ $old_fh = select(OUTPUT_HANDLE);
+ $| = 1;
+ select($old_fh);
+
+Or using the traditional idiom:
+
+ select((select(OUTPUT_HANDLE), $| = 1)[0]);
+
+Or if don't mind slowly loading several thousand lines of module code
+just because you're afraid of the C<$|> variable:
use FileHandle;
- open(DEV, "<+/dev/tty"); # ceci n'est pas une pipe
+ open(DEV, "+</dev/tty"); # ceci n'est pas une pipe
DEV->autoflush(1);
or the newer IO::* modules:
die "$!" unless $sock;
$sock->autoflush();
- $sock->print("GET /\015\012");
- $document = join('', $sock->getlines());
+ print $sock "GET / HTTP/1.0" . "\015\012" x 2;
+ $document = join('', <$sock>);
print "DOC IS: $document\n";
-Note the hardcoded carriage return and newline in their octal
-equivalents. This is the ONLY way (currently) to assure a proper
-flush on all platforms, including Macintosh.
+Note the bizarrely hardcoded carriage return and newline in their octal
+equivalents. This is the ONLY way (currently) to assure a proper flush
+on all platforms, including Macintosh. That the way things work in
+network programming: you really should specify the exact bit pattern
+on the network line terminator. In practice, C<"\n\n"> often works,
+but this is not portable.
-You can use select() and the C<$|> variable to control autoflushing
-(see L<perlvar/$|> and L<perlfunc/select>):
-
- $oldh = select(DEV);
- $| = 1;
- select($oldh);
-
-You'll also see code that does this without a temporary variable, as in
-
- select((select(DEV), $| = 1)[0]);
+See L<perlfaq9> for other examples of fetching URLs over the web.
=head2 How do I change one line in a file/delete a line in a file/insert a line in the middle of a file/append to the beginning of a file?
particular line of a file, insert text into a file, or remove text
from a file.
-(There are exceptions in special circumstances. Replacing a sequence
-of bytes with another sequence of the same length is one. Another is
-using the C<$DB_RECNO> array bindings as documented in L<DB_File>.
-Yet another is manipulating files with all lines the same length.)
+(There are exceptions in special circumstances. You can add or remove at
+the very end of the file. Another is replacing a sequence of bytes with
+another sequence of the same length. Another is using the C<$DB_RECNO>
+array bindings as documented in L<DB_File>. Yet another is manipulating
+files with all lines the same length.)
The general solution is to create a temporary copy of the text file with
-the changes you want, then copy that over the original.
+the changes you want, then copy that over the original. This assumes
+no locking.
$old = $file;
$new = "$file.tmp.$$";
}
close FILE;
+This assumes no funny games with newline translations.
+
=head2 How do I make a temporary file name?
-Use the process ID and/or the current time-value. If you need to have
-many temporary files in one process, use a counter:
+Use the C<new_tmpfile> class method from the IO::File module to get a
+filehandle opened for reading and writing. Use this if you don't
+need to know the file's name.
- BEGIN {
use IO::File;
+ $fh = IO::File->new_tmpfile()
+ or die "Unable to make new temporary file: $!";
+
+Or you can use the C<tmpnam> function from the POSIX module to get a
+filename that you then open yourself. Use this if you do need to know
+the file's name.
+
+ use Fcntl;
+ use POSIX qw(tmpnam);
+
+ # try new temporary filenames until we get one that didn't already
+ # exist; the check should be unnecessary, but you can't be too careful
+ do { $name = tmpnam() }
+ until sysopen(FH, $name, O_RDWR|O_CREAT|O_EXCL);
+
+ # install atexit-style handler so that when we exit or die,
+ # we automatically delete this temporary file
+ END { unlink($name) or die "Couldn't unlink $name : $!" }
+
+ # now go on to use the file ...
+
+If you're committed to doing this by hand, use the process ID and/or
+the current time-value. If you need to have many temporary files in
+one process, use a counter:
+
+ BEGIN {
use Fcntl;
my $temp_dir = -d '/tmp' ? '/tmp' : $ENV{TMP} || $ENV{TEMP};
my $base_name = sprintf("%s/%d-%d-0000", $temp_dir, $$, time());
sub temp_file {
- my $fh = undef;
+ local *FH;
my $count = 0;
- until (defined($fh) || $count > 100) {
+ until (defined(fileno(FH)) || $count++ > 100) {
$base_name =~ s/-(\d+)$/"-" . (1 + $1)/e;
- $fh = IO::File->new($base_name, O_WRONLY|O_EXCL|O_CREAT, 0644)
+ sysopen(FH, $base_name, O_WRONLY|O_EXCL|O_CREAT);
}
- if (defined($fh)) {
- return ($fh, $base_name);
+ if (defined(fileno(FH))
+ return (*FH, $base_name);
} else {
return ();
}
}
}
-Or you could simply use IO::Handle::new_tmpfile.
-
=head2 How can I manipulate fixed-record-length files?
-The most efficient way is using pack() and unpack(). This is faster
-than using substr(). Here is a sample chunk of code to break up and
-put back together again some fixed-format input lines, in this case
-from the output of a normal, Berkeley-style ps:
+The most efficient way is using pack() and unpack(). This is faster than
+using substr() when take many, many strings. It is slower for just a few.
+
+Here is a sample chunk of code to break up and put back together again
+some fixed-format input lines, in this case from the output of a normal,
+Berkeley-style ps:
# sample input line:
# 15158 p5 T 0:00 perl /home/tchrist/scripts/now-what
$PS_T = 'A6 A4 A7 A5 A*';
open(PS, "ps|");
- $_ = <PS>; print;
+ print scalar <PS>;
while (<PS>) {
($pid, $tt, $stat, $time, $command) = unpack($PS_T, $_);
for $var (qw!pid tt stat time command!) {
"\n";
}
+We've used C<$$var> in a way that forbidden by C<use strict 'refs'>.
+That is, we've promoted a string to a scalar variable reference using
+symbolic references. This is ok in small programs, but doesn't scale
+well. It also only works on global variables, not lexicals.
+
=head2 How can I make a filehandle local to a subroutine? How do I pass filehandles between subroutines? How do I make an array of filehandles?
-You may have some success with typeglobs, as we always had to use
-in days of old:
+The fastest, simplest, and most direct way is to localize the typeglob
+of the filehandle in question:
- local(*FH);
+ local *TmpHandle;
-But while still supported, that isn't the best to go about getting
-local filehandles. Typeglobs have their drawbacks. You may well want
-to use the C<FileHandle> module, which creates new filehandles for you
-(see L<FileHandle>):
+Typeglobs are fast (especially compared with the alternatives) and
+reasonably easy to use, but they also have one subtle drawback. If you
+had, for example, a function named TmpHandle(), or a variable named
+%TmpHandle, you just hid it from yourself.
- use FileHandle;
sub findme {
- my $fh = FileHandle->new();
- open($fh, "</etc/hosts") or die "no /etc/hosts: $!";
- while (<$fh>) {
+ local *HostFile;
+ open(HostFile, "</etc/hosts") or die "no /etc/hosts: $!";
+ local $_; # <- VERY IMPORTANT
+ while (<HostFile>) {
print if /\b127\.(0\.0\.)?1\b/;
}
- # $fh automatically closes/disappears here
+ # *HostFile automatically closes/disappears here
+ }
+
+Here's how to use this in a loop to open and store a bunch of
+filehandles. We'll use as values of the hash an ordered
+pair to make it easy to sort the hash in insertion order.
+
+ @names = qw(motd termcap passwd hosts);
+ my $i = 0;
+ foreach $filename (@names) {
+ local *FH;
+ open(FH, "/etc/$filename") || die "$filename: $!";
+ $file{$filename} = [ $i++, *FH ];
}
-Internally, Perl believes filehandles to be of class IO::Handle. You
-may use that module directly if you'd like (see L<IO::Handle>), or
-one of its more specific derived classes.
+ # Using the filehandles in the array
+ foreach $name (sort { $file{$a}[0] <=> $file{$b}[0] } keys %file) {
+ my $fh = $file{$name}[1];
+ my $line = <$fh>;
+ print "$name $. $line";
+ }
+
+If you want to create many, anonymous handles, you should check out the
+Symbol, FileHandle, or IO::Handle (etc.) modules. Here's the equivalent
+code with Symbol::gensym, which is reasonably light-weight:
+
+ foreach $filename (@names) {
+ use Symbol;
+ my $fh = gensym();
+ open($fh, "/etc/$filename") || die "open /etc/$filename: $!";
+ $file{$filename} = [ $i++, $fh ];
+ }
-Once you have IO::File or FileHandle objects, you can pass them
-between subroutines or store them in hashes as you would any other
-scalar values:
+Or here using the semi-object-oriented FileHandle, which certainly isn't
+light-weight:
use FileHandle;
- # Storing filehandles in a hash and array
foreach $filename (@names) {
- my $fh = new FileHandle($filename) or die;
- $file{$filename} = $fh;
- push(@files, $fh);
+ my $fh = FileHandle->new("/etc/$filename") or die "$filename: $!";
+ $file{$filename} = [ $i++, $fh ];
}
- # Using the filehandles in the array
- foreach $file (@files) {
- print $file "Testing\n";
+Please understand that whether the filehandle happens to be a (probably
+localized) typeglob or an anonymous handle from one of the modules,
+in no way affects the bizarre rules for managing indirect handles.
+See the next question.
+
+=head2 How can I use a filehandle indirectly?
+
+An indirect filehandle is using something other than a symbol
+in a place that a filehandle is expected. Here are ways
+to get those:
+
+ $fh = SOME_FH; # bareword is strict-subs hostile
+ $fh = "SOME_FH"; # strict-refs hostile; same package only
+ $fh = *SOME_FH; # typeglob
+ $fh = \*SOME_FH; # ref to typeglob (bless-able)
+ $fh = *SOME_FH{IO}; # blessed IO::Handle from *SOME_FH typeglob
+
+Or to use the C<new> method from the FileHandle or IO modules to
+create an anonymous filehandle, store that in a scalar variable,
+and use it as though it were a normal filehandle.
+
+ use FileHandle;
+ $fh = FileHandle->new();
+
+ use IO::Handle; # 5.004 or higher
+ $fh = IO::Handle->new();
+
+Then use any of those as you would a normal filehandle. Anywhere that
+Perl is expecting a filehandle, an indirect filehandle may be used
+instead. An indirect filehandle is just a scalar variable that contains
+a filehandle. Functions like C<print>, C<open>, C<seek>, or the functions or
+the C<E<lt>FHE<gt>> diamond operator will accept either a read filehandle
+or a scalar variable containing one:
+
+ ($ifh, $ofh, $efh) = (*STDIN, *STDOUT, *STDERR);
+ print $ofh "Type it: ";
+ $got = <$ifh>
+ print $efh "What was that: $got";
+
+Of you're passing a filehandle to a function, you can write
+the function in two ways:
+
+ sub accept_fh {
+ my $fh = shift;
+ print $fh "Sending to indirect filehandle\n";
}
- # You have to do the { } ugliness when you're specifying the
- # filehandle by anything other than a simple scalar variable.
- print { $files[2] } "Testing\n";
+Or it can localize a typeglob and use the filehandle directly:
- # Passing filehandles to subroutines
- sub debug {
- my $filehandle = shift;
- printf $filehandle "DEBUG: ", @_;
+ sub accept_fh {
+ local *FH = shift;
+ print FH "Sending to localized filehandle\n";
}
- debug($fh, "Testing\n");
+Both styles work with either objects or typeglobs of real filehandles.
+(They might also work with strings under some circumstances, but this
+is risky.)
+
+ accept_fh(*STDOUT);
+ accept_fh($handle);
+
+In the examples above, we assigned the filehandle to a scalar variable
+before using it. That is because only simple scalar variables,
+not expressions or subscripts into hashes or arrays, can be used with
+built-ins like C<print>, C<printf>, or the diamond operator. These are
+illegal and won't even compile:
+
+ @fd = (*STDIN, *STDOUT, *STDERR);
+ print $fd[1] "Type it: "; # WRONG
+ $got = <$fd[0]> # WRONG
+ print $fd[2] "What was that: $got"; # WRONG
+
+With C<print> and C<printf>, you get around this by using a block and
+an expression where you would place the filehandle:
+
+ print { $fd[1] } "funny stuff\n";
+ printf { $fd[1] } "Pity the poor %x.\n", 3_735_928_559;
+ # Pity the poor deadbeef.
+
+That block is a proper block like any other, so you can put more
+complicated code there. This sends the message out to one of two places:
+
+ $ok = -x "/bin/cat";
+ print { $ok ? $fd[1] : $fd[2] } "cat stat $ok\n";
+ print { $fd[ 1+ ($ok || 0) ] } "cat stat $ok\n";
+
+This approach of treating C<print> and C<printf> like object methods
+calls doesn't work for the diamond operator. That's because it's a
+real operator, not just a function with a comma-less argument. Assuming
+you've been storing typeglobs in your structure as we did above, you
+can use the built-in function named C<readline> to reads a record just
+as C<E<lt>E<gt>> does. Given the initialization shown above for @fd, this
+would work, but only because readline() require a typeglob. It doesn't
+work with objects or strings, which might be a bug we haven't fixed yet.
+
+ $got = readline($fd[0]);
+
+Let it be noted that the flakiness of indirect filehandles is not
+related to whether they're strings, typeglobs, objects, or anything else.
+It's the syntax of the fundamental operators. Playing the object
+game doesn't help you at all here.
=head2 How can I set up a footer format to be used with write()?
: ( $ENV{HOME} || $ENV{LOGDIR} )
}ex;
-=head2 How come when I open the file read-write it wipes it out?
+=head2 How come when I open a file read-write it wipes it out?
Because you're using something like this, which truncates the file and
I<then> gives you read-write access:
- open(FH, "+> /path/name"); # WRONG
+ open(FH, "+> /path/name"); # WRONG (almost always)
Whoops. You should instead use this, which will fail if the file
-doesn't exist.
+doesn't exist. Using "E<gt>" always clobbers or creates.
+Using "E<lt>" never does either. The "+" doesn't change this.
- open(FH, "+< /path/name"); # open for update
+Here are examples of many kinds of file opens. Those using sysopen()
+all assume
-If this is an issue, try:
+ use Fcntl;
- sysopen(FH, "/path/name", O_RDWR|O_CREAT, 0644);
+To open file for reading:
-Error checking is left as an exercise for the reader.
+ open(FH, "< $path") || die $!;
+ sysopen(FH, $path, O_RDONLY) || die $!;
+
+To open file for writing, create new file if needed or else truncate old file:
+
+ open(FH, "> $path") || die $!;
+ sysopen(FH, $path, O_WRONLY|O_TRUNC|O_CREAT) || die $!;
+ sysopen(FH, $path, O_WRONLY|O_TRUNC|O_CREAT, 0666) || die $!;
+
+To open file for writing, create new file, file must not exist:
+
+ sysopen(FH, $path, O_WRONLY|O_EXCL|O_CREAT) || die $!;
+ sysopen(FH, $path, O_WRONLY|O_EXCL|O_CREAT, 0666) || die $!;
+
+To open file for appending, create if necessary:
+
+ open(FH, ">> $path") || die $!;
+ sysopen(FH, $path, O_WRONLY|O_APPEND|O_CREAT) || die $!;
+ sysopen(FH, $path, O_WRONLY|O_APPEND|O_CREAT, 0666) || die $!;
+
+To open file for appending, file must exist:
+
+ sysopen(FH, $path, O_WRONLY|O_APPEND) || die $!;
+
+To open file for update, file must exist:
+
+ open(FH, "+< $path") || die $!;
+ sysopen(FH, $path, O_RDWR) || die $!;
+
+To open file for update, create file if necessary:
+
+ sysopen(FH, $path, O_RDWR|O_CREAT) || die $!;
+ sysopen(FH, $path, O_RDWR|O_CREAT, 0666) || die $!;
+
+To open file for update, file must not exist:
+
+ sysopen(FH, $path, O_RDWR|O_EXCL|O_CREAT) || die $!;
+ sysopen(FH, $path, O_RDWR|O_EXCL|O_CREAT, 0666) || die $!;
+
+To open a file without blocking, creating if necessary:
+
+ sysopen(FH, "/tmp/somefile", O_WRONLY|O_NDELAY|O_CREAT)
+ or die "can't open /tmp/somefile: $!":
+
+Be warned that neither creation nor deletion of files is guaranteed to
+be an atomic operation over NFS. That is, two processes might both
+successful create or unlink the same file! Therefore O_EXCL
+isn't so exclusive as you might wish.
=head2 Why do I sometimes get an "Argument list too long" when I use <*>?
real rename(), though, which preserves metainformation like
permissions, timestamps, inode info, etc.
+The newer version of File::Copy export a move() function.
+
=head2 How can I lock a file?
Perl's builtin flock() function (see L<perlfunc> for details) will call
=back
-The CPAN module File::Lock offers similar functionality and (if you
-have dynamic loading) won't require you to rebuild perl if your
-flock() can't lock network files.
-
=head2 What can't I just open(FH, ">file.lock")?
A common bit of code B<NOT TO USE> is this:
which must be done in one. That's why computer hardware provides an
atomic test-and-set instruction. In theory, this "ought" to work:
- sysopen(FH, "file.lock", O_WRONLY|O_EXCL|O_CREAT, 0644)
+ sysopen(FH, "file.lock", O_WRONLY|O_EXCL|O_CREAT)
or die "can't open file.lock: $!":
except that lamentably, file creation (and deletion) is not atomic
=head2 I still don't get locking. I just want to increment the number in the file. How can I do this?
Didn't anyone ever tell you web-page hit counters were useless?
+They don't count number of hits, they're a waste of time, and they serve
+only to stroke the writer's vanity. Better to pick a random number.
+It's more realistic.
-Anyway, this is what to do:
+Anyway, this is what you can do if you can't help yourself.
use Fcntl;
- sysopen(FH, "numfile", O_RDWR|O_CREAT, 0644) or die "can't open numfile: $!";
+ sysopen(FH, "numfile", O_RDWR|O_CREAT) or die "can't open numfile: $!";
flock(FH, 2) or die "can't flock numfile: $!";
$num = <FH> || 0;
seek(FH, 0, 0) or die "can't rewind numfile: $!";
Locking and error checking are left as an exercise for the reader.
Don't forget them, or you'll be quite sorry.
-Don't forget to set binmode() under DOS-like platforms when operating
-on files that have anything other than straight text in them. See the
-docs on open() and on binmode() for more details.
-
=head2 How do I get a file's timestamp in perl?
If you want to retrieve the time at which the file was last read,
open (FH, "| tee file1 file2 file3");
-Otherwise you'll have to write your own multiplexing print function --
-or your own tee program -- or use Tom Christiansen's, at
-http://www.perl.com/CPAN/authors/id/TOMC/scripts/tct.gz, which is
-written in Perl.
+Or even:
+
+ # make STDOUT go to three files, plus original STDOUT
+ open (STDOUT, "| tee file1 file2 file3") or die "Teeing off: $!\n";
+ print "whatever\n" or die "Writing: $!\n";
+ close(STDOUT) or die "Closing: $!\n";
-In theory a IO::Tee class could be written, but to date we haven't
-seen such.
+Otherwise you'll have to write your own multiplexing print
+function -- or your own tee program -- or use Tom Christiansen's,
+at http://www.perl.com/CPAN/authors/id/TOMC/scripts/tct.gz, which is
+written in Perl and offers much greater functionality
+than the stock version.
=head2 How can I read in a file by paragraphs?
=head2 How can I tell if there's a character waiting on a filehandle?
-You should check out the Frequently Asked Questions list in
+The very first thing you should do is look into getting the Term::ReadKey
+extension from CPAN. It now even has limited support for closed, proprietary
+(read: not open systems, not POSIX, not Unix, etc) systems.
+
+You should also check out the Frequently Asked Questions list in
comp.unix.* for things like this: the answer is essentially the same.
It's very system dependent. Here's one solution that works on BSD
systems:
return $nfd = select($rin,undef,undef,0);
}
-You should look into getting the Term::ReadKey extension from CPAN.
+If you want to find out how many characters are waiting,
+there's also the FIONREAD ioctl call to be looked at.
-=head2 How do I open a file without blocking?
+The I<h2ph> tool that comes with Perl tries to convert C include
+files to Perl code, which can be C<require>d. FIONREAD ends
+up defined as a function in the I<sys/ioctl.ph> file:
-You need to use the O_NDELAY or O_NONBLOCK flag from the Fcntl module
-in conjunction with sysopen():
+ require 'sys/ioctl.ph';
- use Fcntl;
- sysopen(FH, "/tmp/somefile", O_WRONLY|O_NDELAY|O_CREAT, 0644)
- or die "can't open /tmp/somefile: $!":
+ $size = pack("L", 0);
+ ioctl(FH, FIONREAD(), $size) or die "Couldn't call ioctl: $!\n";
+ $size = unpack("L", $size);
-=head2 How do I create a file only if it doesn't exist?
+If I<h2ph> wasn't installed or doesn't work for you, you can
+I<grep> the include files by hand:
-You need to use the O_CREAT and O_EXCL flags from the Fcntl module in
-conjunction with sysopen():
+ % grep FIONREAD /usr/include/*/*
+ /usr/include/asm/ioctls.h:#define FIONREAD 0x541B
- use Fcntl;
- sysopen(FH, "/tmp/somefile", O_WRONLY|O_EXCL|O_CREAT, 0644)
- or die "can't open /tmp/somefile: $!":
+Or write a small C program using the editor of champions:
-Be warned that neither creation nor deletion of files is guaranteed to
-be an atomic operation over NFS. That is, two processes might both
-successful create or unlink the same file!
+ % cat > fionread.c
+ #include <sys/ioctl.h>
+ main() {
+ printf("%#08x\n", FIONREAD);
+ }
+ ^D
+ % cc -o fionread fionread
+ % ./fionread
+ 0x4004667f
+
+And then hard-code it, leaving porting as an exercise to your successor.
+
+ $FIONREAD = 0x4004667f; # XXX: opsys dependent
+
+ $size = pack("L", 0);
+ ioctl(FH, $FIONREAD, $size) or die "Couldn't call ioctl: $!\n";
+ $size = unpack("L", $size);
+
+FIONREAD requires a filehandle connected to a stream, meaning sockets,
+pipes, and tty devices work, but I<not> files.
=head2 How do I do a C<tail -f> in perl?
$fd = $ENV{MHCONTEXTFD};
open(MHCONTEXT, "<&=$fd"); # like fdopen(3S)
-Error checking has been left as an exercise for the reader.
+Note that "E<lt>&STDIN" makes a copy, but "E<lt>&=STDIN" make
+an alias. That means if you close an aliased handle, all
+aliases become inaccessible. This is not true with
+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?
Because even on non-Unix ports, Perl's glob function follows standard
Unix globbing semantics. You'll need C<glob("*")> to get all (non-hidden)
-files.
+files. This makes glob() portable.
=head2 Why does Perl let me delete read-only files? Why does C<-i> clobber protected files? Isn't this a bug in Perl?
This is elaborately and painstakingly described in the "Far More Than
-You Every Wanted To Know" in
+You Ever Wanted To Know" in
http://www.perl.com/CPAN/doc/FMTEYEWTK/file-dir-perms .
The executive summary: learn how your filesystem works. The
rand($.) < 1 && ($line = $_) while <>;
This has a significant advantage in space over reading the whole
-file in.
+file in. A simple proof by induction is available upon
+request if you doubt its correctness.
=head1 AUTHOR AND COPYRIGHT
-Copyright (c) 1997 Tom Christiansen and Nathan Torkington.
-All rights reserved. See L<perlfaq> for distribution information.
-
+Copyright (c) 1997, 1998 Tom Christiansen and Nathan Torkington.
+All rights reserved.
+
+When included as part of the Standard Version of Perl, or as part of
+its complete documentation whether printed or otherwise, this work
+may be distributed only under the terms of Perl's Artistic License.
+Any distribution of this file or derivatives thereof I<outside>
+of that package require that special arrangements be made with
+copyright holder.
+
+Irrespective of its distribution, all code examples in this file
+are hereby placed into the public domain. You are permitted and
+encouraged to use this code in your own programs for fun
+or for profit as you see fit. A simple comment in the code giving
+credit would be courteous but is not required.
projects / p5sagit/p5-mst-13.2.git / blobdiff