IO::Wrap - wrap raw filehandles in IO::Handle interface


IO::Wrap - wrap raw filehandles in IO::Handle interface


   use IO::Wrap;
   ### Do stuff with any kind of filehandle (including a bare globref), or 
   ### any kind of blessed object that responds to a print() message.
   sub do_stuff {
       my $fh = shift;         
       ### At this point, we have no idea what the user gave us... 
       ### a globref? a FileHandle? a scalar filehandle name?
       $fh = wraphandle($fh);  
       ### At this point, we know we have an IO::Handle-like object!
       $fh->print("Hey there!");


Let's say you want to write some code which does I/O, but you don't want to force the caller to provide you with a FileHandle or IO::Handle object. You want them to be able to say:


And even:


Sure, one way to do it is to force the caller to use tiehandle(). But that puts the burden on them. Another way to do it is to use IO::Wrap, which provides you with the following functions:

wraphandle SCALAR
This function will take a single argument, and ``wrap'' it based on what it seems to be...

If you get back an IO::Wrap object, it will obey a basic subset of the IO:: interface. That is, the following methods (note: I said methods, not named operators) should work on the thing you get back:

    print ARGS...
    seek POS,WHENCE


Clearly, when wrapping a raw external filehandle (like \*STDOUT), I didn't want to close the file descriptor when the ``wrapper'' object is destroyed... since the user might not appreciate that! Hence, there's no DESTROY method in this class.

When wrapping a FileHandle object, however, I believe that Perl will invoke the FileHandle::DESTROY when the last reference goes away, so in that case, the filehandle is closed if the wrapped FileHandle really was the last reference to it.


This module does not allow you to wrap filehandle names which are given as strings that lack the package they were opened in. That is, if a user opens FOO in package Foo, they must pass it to you either as \*FOO or as "Foo::FOO". However, "STDIN" and friends will work just fine.


$Id:,v 1.2 2005/02/10 21:21:53 dfs Exp $


Primary Maintainer
David F. Skoll (

Original Author
Eryq ( President, ZeeGee Software Inc (
 IO::Wrap - wrap raw filehandles in IO::Handle interface