The tie() function binds a variable to a class (package) that will provide
the implementation for access methods for that variable. Once this magic
has been performed, accessing a tied variable automatically triggers
-method calls in the proper class. All of the complexity of the class is
+method calls in the proper class. The complexity of the class is
hidden behind magic methods calls. The method names are in ALL CAPS,
which is a convention that Perl uses to indicate that they're called
implicitly rather than explicitly--just like the BEGIN() and END()
=back
-Note that functions such as keys() and values() may return huge array
-values when used on large objects, like DBM files. You may prefer to
-use the each() function to iterate over such. Example:
+Note that functions such as keys() and values() may return huge lists
+when used on large objects, like DBM files. You may prefer to use the
+each() function to iterate over such. Example:
# print out history file offsets
use NDBM_File;
This is partially implemented now.
A class implementing a tied filehandle should define the following
-methods: TIEHANDLE, at least one of PRINT, PRINTF, READLINE, GETC, or READ,
-and possibly DESTROY.
+methods: TIEHANDLE, at least one of PRINT, PRINTF, WRITE, READLINE, GETC,
+READ, and possibly CLOSE and DESTROY.
It is especially useful when perl is embedded in some other program,
where output to STDOUT and STDERR may have to be redirected in some
sub TIEHANDLE { print "<shout>\n"; my $i; bless \$i, shift }
+=item WRITE this, LIST
+
+This method will be called when the handle is written to via the
+C<syswrite> function.
+
+ sub WRITE {
+ $r = shift;
+ my($buf,$len,$offset) = @_;
+ print "WRITE called, \$buf=$buf, \$len=$len, \$offset=$offset";
+ }
+
=item PRINT this, LIST
This method will be triggered every time the tied handle is printed to
print sprintf($fmt, @_)."\n";
}
-=item READ this LIST
+=item READ this, LIST
This method will be called when the handle is read from via the C<read>
or C<sysread> functions.
sub GETC { print "Don't GETC, Get Perl"; return "a"; }
+=item CLOSE this
+
+This method will be called when the handle is closed via the C<close>
+function.
+
+ sub CLOSE { print "CLOSE called.\n" }
+
=item DESTROY this
As with the other types of ties, this method will be called when the