Even unbuffered output to STDERR in a BEGIN block doesn't show up

Where are you expecting the ouput to "show up"?

BrowserUk,
Here is an idea of what I am talking about (actual code is at home):

#!/usr/bin/perl
BEGIN {
    open(STDERR, '>', 'C:/app_name/err.log' or die $!;
    select STDERR;
    $| = 1; # un-necessary, I know
    print STDERR "hello world\n";
}
use lib 'C:/app_name';
use strict;
use warnings;
use My::App;

my $app = My::App->new(cfg => 'C:/app_name/app.cfg') or die "Didn't ge
+t past this point\n";

print STDERR "Ok, got here\n";

while ($app->run_ok) {
    print STDERR "Inside while loop\n";
    $app->do_things();
    $app->rest_for_a_while();
}
print STDERR "finishing up now\n";
[download]

When I start the service, the err.log file is created but is 0 bytes. After 5 minutes or so, I stop the service and the following output shows up in the err.log file (hello world and Ok, Got here)

Cheers - L~R

The following works for me on XP:

1. Install SrvAny with: instsrv "YourService" c:\the\Path\to\SrvAny.exe
2. Use Regedit to add the following keys:

   [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SrvAny\Parameter
   +s]
   "Application"="\\perl\\bin\\wperl.exe \\test\\service.pl"
   [download]

   Modify the paths to your wperl and script accordingly.

3. Go into the Service Manager, double-click "YourService". Select the "Log-on" tab from the properties dialog and check the "Allow service to interact with desktop" option. Apply and save.
4. This is my minimal service.pl:

   #! perl -slw
   use strict;
   use Win32;
   
   open LOG, '>', 'c:\test\service.log' or die;
   select LOG;
   $|++;
   
   Win32::MsgBox( 'From service.pl at ' . localtime,  0, "Service.pl" );
   
   while( sleep 5 ) {
       Win32::MsgBox( 'From service.pl at ' . localtime,  0, "Service.pl"
   + );
       print scalar localtime;
   }
   
   close LOG;
   [download]

   It pops up a message box on startup and every 5 seconds thereafter. (And bloody annoying it is too :)

   It creates and writes to the log file.

YMMV on Vista.

---

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ikegami,
Maybe you'll have better luck using wperl.exe instead of perl.exe.

Interesting thought. I wonder where you came up with it?

This application currently doesn't write to STDOUT, STDERR, or read input from STDIN. It does write information to a SQLite database as well as launch external GUI applications (Firefox via WWW::Selenium as well as interface Outlook via Win32::API. It runs fine from the command line but not as a service (no work is performed). I am happy to give wperl.exe a try later but I am not sure why it would work where perl.exe fails.

Are you thinking that it is specifically my application and not just any perl script that won't work using SrvAny with 5.10 on Vista?

Cheers - L~R

It's simpler than that. I am thinking that Perl might attempt to access the console even if it doesn't end being used.