I’m just beginning to research the issue of signal-definitions in Strawberry. Any links helpful.

Otherwise it can sometimes be difficult to see from the transcript whether the alarms worked as they should or not.

It seems to me that there is a bug in Perl that causes alarms to be silently cancelled if you do a can_read().

Nasty shit. Takes days to debug. Don’t use signals in Perl.

The $SIG{ALRM} code actually runs. But it runs much later than the alarm() call requested.

In the example I whipped up, I had a Perl loop running a few lines of code, the loop reiterates every second, the short of the long being that there are lots of Perl opcodes being executed at the point in time where the alarm should go off, meaning that safe signals should work fine. But they don’t.

Also tried Strawberry Perl 5.10.1.0.beta_1, which exhibits exactly the same bug.

The operating system is Windows 7, which is significant because the alarm() implementation added in ActivePerl 5.8.3 is said to be broken with the new SetTimer() semantics introduced with Windows Server 2003.

(Tried Cygwin Perl too, it died with the usual slew of fork / dll loading errors that cygwin exhibits when you try to do something advanced with it.. Such as installing a CPAN package on a completely blank vanilla installation )

I have to ask what you needed to rebase in Strawberry Perl to get it to work?

Let me know – I’d like to do it in the build for the October 2009 versions!

I have some similar restrictions at work but I can locally install Perl modules. I’m impressed that you’re able to use Windows 7 on your laptop. We’re stuck with XP, not that I think that is a really bad thing mind you.

Hi Sue (nice name by the way ),

As you can probably tell, I’m more of a server guy than a GUI guy although I’ve hacked together a few (ugly) trivial GUIs using Tcl/Tk and WxPython / C++ w/ Wx. If someone asked me to write a GUI on Windows, and gave me a fair bit of flexibility of technology, my choices in rough order of preference would probably be:

Catalyst + JQuery based Web front end
Clojure / Swing (no experience of Clojure yet though)
WxPython (you can program most Perl in Python!)
Emacs-based GUI if appropriate (see for example here)
Wx::Perl

Not really related to this blog entry, but: I like reading your emacs/perl/programming-in-general columns. I wondered if you had any insight into GUI programming in Perl (particularly under Windows).

So far as I can see, there’s Wx, Qt, Tk, and Win32::GUI.

Wx looks halfway decent, but all the docs are written for the C++ programmer and have been poorly translated into Perl (as in, there is documentation for stuff that doesn’t exist in Wx::Perl, and vice-versa).

I haven’t tried Qt.

Tk is ancient and crufty. It works, it’s reasonably well documented, but it looks like crap, especially on Windows. It also doesn’t have some modern Windows UI amenities.

Win32::GUI has okay documentation, with some gaping holes, has some inconsistencies in implementation, has no UI development environment (like Glade for Wx). It’s hard to extend. Also, unlike the others, it works only on Windows.

All of these options seem like a tremendous amount of work for what you get, with steep and confusing learning curves to boot. Most of them have crappy docs, and some of them make crappy UIs. It seems like a total lose, no matter which one you choose.

Do you have any observations or insights (or recommendations)? Thanks.

I’m on pretty locked down hardware/firewall at work so when I try to do anything like ruby or Perl I can’t get gem/cpan (anything not endorsed by the man) to work.

That being said, I just upgraded my corporate laptop to Windows 7 RC1 Enterprise and it came with MS Powershell 2 CTP3 — that plus EmacsW32 is just about good enough for me.