Watching Perl die() under Win32


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Watching Perl die() under Win32

by Chmrr (Vicar)

on Feb 28, 2001 at 11:09 UTC ( #61300=snippet: print w/ replies, xml )

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Description:

One of the many things that I hate about Windows is how it automatically ("helpfully") closes DOS windows when they quit. This is most annoying when the program die()d, as you don't get a chance to read the error message. So here's a snippet that detects if the program was double-clicked, or run from a command line, and alters %SIG{__DIE__} appropriatly.

Of course, Windows 9* does this differently than Windows NT/2000, so there are two different environment variables that get checked. Actually, I only had a Windows 98 and a Windows 2000 machine to test this on, so /msg me if this works / doesn't work on Windows 95 or NT.

$SIG{__DIE__} = sub {
  # PROMPT is for NT/2000, CMDLINE is for 95/98
  return unless !defined $ENV{PROMPT} or (defined $ENV{CMDLINE} and $E
+NV{CMDLINE} eq 'WIN');
  print shift,"This window will close in 10 seconds." and sleep 10 and
+ exit;
} if $^O =~ /Win32/;

Update: Per tye's suggestion, I moved the return unless $^O =~ /Win32/ outside of the __DIE__ assignment, so the handler is not even changed if we're not under Windows.

Update the second: A fellow monk has made this code into a module and put it on CPAN as Win32::Die. Check it out!

Comment on Watching Perl die() under Win32 Select or Download Code
(tye)Re: Watching Perl die() under Win32 by tye (Archbishop) on Feb 28, 2001 at 11:39 UTC
I'd rather you check for Win32 first and just not set a __DIE__ handle if one isn't needed. Otherwise, quite handy. - tye (but my friends call me "Tye")	[reply]
Re: (tye)Re: Watching Perl die() under Win32 by Chmrr (Vicar) on Feb 28, 2001 at 11:42 UTC
True -- so you would move the `return unless $^O =~ /Win32/` outside the __DIE__ handler? Makes sense. (There is the sound of an edit being made..) perl -e 'print "I love $^X$\"$]!$/"#$&V"+@( NO CARRIER'	[reply] [d/l]
MsgBox vs. print by osfameron (Hermit) on Feb 28, 2001 at 14:19 UTC
The PROMPT variable is also not set from the Start - Run command. Another usage for this would be to determine whether to print to a console, or to do a Win32::MsgBox instead. (I tried to figure out how the script could figure where it was called from some time ago and couldn't work it out...) Thanks! Cheerio! Osfameron	[reply]
Re: MsgBox vs. print by Anonymous Monk on Aug 25, 2003 at 01:21 UTC
As far Windows 98SE is concerned, the PROMPT is set $p$g whether a script is invoked from the command line, clicked, or from the Start-Run dialog box. The CMDLINE is set to whatever was typed on the command line and to WIN if invoked by clicking or from the Start-Run box. If you use the Start-Run box you can pass arguments just as you can from the command line.	[reply]
Re: Watching Perl die() under Win32 by Ido (Hermit) on Mar 02, 2001 at 18:03 UTC
I don't know about Win2k or NT. But on 95/98/ME the /k flag of command.com might be useful. Changing the Open "Action" of .pl files (In folder options->file types) to "command.com /k c:\perl\bin\perl.exe" should do.	[reply]
Re: Re: Watching Perl die() under Win32 by Chmrr (Vicar) on Mar 03, 2001 at 03:53 UTC
True. I would point out that the solution I provided above is also useful after programs have been run through perl2exe or any equivalent -- which was actually my original impetus. perl -e 'print "I love $^X$\"$]!$/"#$&V"+@( NO CARRIER'	[reply]
Re: Watching Perl die() under Win32 by draconis22 (Initiate) on Mar 09, 2001 at 10:26 UTC
I personally recommend creating a batch file that has something like perl.exe -w %1 pause Whala.... as long as perl is set in your enviroment variables, all you have to do is run through the batch file instead of adding in code to each project. If you use Ultraedit, you can even plug this into a macro and it saves you lots of time-and headaches Derek	[reply]
Re: Re: Watching Perl die() under Win32 by Anonymous Monk on Apr 02, 2001 at 05:31 UTC
Doesn't DOS shells (I use that term loosely) offer an errorlevel check? So, you could pause only if the process returns a non-zero exist status: perl.exe -w %1 if errorlevel 1 pause	[reply]

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Watching Perl die() under Win32

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