IO(3) User Contributed Perl Documentation IO(3)

# [NAME](#NAME)

Tk::IO - high level interface to Tk's 'fileevent' mechanism

# [SYNOPSIS](#SYNOPSIS)

```
  my $fh = Tk::IO->new(-linecommand => callback, -childcommand => callback);
  $fh->exec("command")
  $fh->wait
  $fh->kill
```

# [WARNING](#WARNING)

INTERFACES TO THIS MODULE MAY CHANGE AS PERL'S IO EVOLVES AND WITH PORT OF TK4.1

# [DESCRIPTION](#DESCRIPTION)

Tk::IO is now layered on perl's IO::Handle class. Interfaces have changed, and are still evolving.

In theory C methods which enable non-blocking IO as in earlier Tk-b* release(s) are still there. I have not changed them to use perl's additional Configure information, or tested them much.

Assumption is that **exec** is used to fork a child process and a callback is called each time a complete line arrives up the implied pipe.

"line" should probably be defined in terms of perl's input record separator but is not yet.

The -childcommand callback is called when end-of-file occurs.

$fh->**wait** can be used to wait for child process while processing other Tk events.

$fh->**kill** can be used to send signal to child process.

# [BUGS](#BUGS)

Still not finished. Idea is to use "exec" to emulate "system" in a non-blocking manner.

2026-10-25 perl v5.44.0

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Document: Tk::IO(3pm) from perl-tk 804.036-r12 (Chainguard OS)
Source: https://github.com/eserte/perl-tk