\" on the WinXP Command Line

[Ardemus]

This is just a curiosity. I understand Perl's behavior when parsing \" off of the win32 command line. Is there a way to handle the behavior in Perl, rather than expecting the user to adapt to my program?

For those who aren't familiar with this behavior:

foreach (@ARGV){print "'$_'\n";}

EXAMPLE A
parameters - "A A\" B
output - 'A A" B'

EXAMPLE B
parameters - "A A" B
output - 'A A'
output - 'B'

#example B is how batch files (and all apps I've used) behave in
windows.  Also, \ is the path delimiter in windows, so it's natural
to have one at the end of an argument.

I've asked on the chatterbox, and one wise monk suggested that user education was the best solution. This is a fine for my purposes. However, I'm still curious if anyone has another idea?

[John M. Dlugosz]

The perl.exe program contains common code supplied by the compiler that parses the command tail into words which it then passes to main() as argv. If you recompile perl.exe, you can change that with some effort, or ignore it with less effort: at the top of main call GetCommandLine, parse it the way you please, re-point argv to your own array. The rest of the program will be none the wiser.

But if you don't mind perl itself getting flags in its usual way, you can affect parsing of the arguments to your script from within Perl. Ignore ARGV and parse the string from GetCommandLine within the program. If it's not available already in some module, just use Win32::API to import it.

—John

[Ardemus]

Thanks folks. Between your comments and a quick search (Is it possible to include GetOpt flags in $0), here is a stab at reading the command line directly:

if ($^O=~/win/){
    use Win32::API;
    my $GetCommandLine = Win32::API->new('kernel32', 'GetCommandLine',
+ [ ] , 'P' );
    $cmdline = $GetCommandLine->Call();
    #Parse Command Line, into @ARGV if desired
}

I haven't gotten it to work on my machine yet (the error follows), but I think that it's a configuration issue on my end. Thanks again.

Can't locate Win32/API.pm in @INC (@INC contains: D:/Exoddus/Util/Tool
+s/Scripts C:\Perl\lib C:/Perl/lib C:/Perl/site/lib .) at C:\Documents
+ and Settings\nburger
\Desktop\PerlTemp\dirComptest.pl line 4.
BEGIN failed--compilation aborted at C:\Documents and Settings\nburger
+\Desktop\PerlTemp\dirComptest.pl line 4.

[BrowserUk]

This will let you get at the command line without it being messed with.

#! perl -slw
use strict;
use Win32::API::Prototype;

ApiLink( 'kernel32', 'PVOID GetCommandLine(void)' );

my $cmdline = GetCommandLine( 0 );

my( $exe, $switches, $script, $params )
    = $cmdline =~ m[(\S+)\s+(-\S+)?\s+"([^"]+)"\s*(.*$)];

print "Script params: '$params'";

__END__
P:\test>331797 "A A" B
Script params: '"A A" B'

P:\test>331797 "A A\" B
Script params: '"A A\" B'

[NetWallah]

• Its not clear what behaviour you are expecting.
• This is OT, since your question relates to Win32 command line argument passing, rather than perl.
That said, - if you want 2 parameters passed in, with a trailing '\', try passing the params as '"A A\\" B"':

>perl -e "foreach (@ARGV){print qq('$_'\n);}" "A A\\" B"
'A A\'
'B'

perl never gets a chance to parse the escaped "\" - that is done by the cmd interpreter.

Update: Aah - learned something today - there is a backdoor way to get the args after all! .. see nodes below.

[Ardemus]

I'm sorry, I'm expecting all arguments (even those ending with a backslash) to be parsed as they are in example B.

As John comments a little later: this is an issue with how Perl handles standard Windows command line arguments (the goal was to avoid deviating from that standard syntax).

I am looking for Perl based solutions (like the one that John provided). Is this the incorrect forum for that type of question? I'm new to the Perl Monks, so I applogize if I chose the wrong forum.

Thanks

[hardburn]

Is there a way to handle the behavior in Perl

Afraid not. The shell parses the arguments before Perl ever sees them.

[John M. Dlugosz]

Not in Windows. The shell passes the entire command-line "tail" to the .exe file, and that parses before calling main().

[Roger]

What's wrong with Getopt::Long?

[NetWallah]

Roger: Getopt::Long won't work because perl (and program modules) only see what the command shell passes them, after the command shell is done interpreting (in this case, mis-interpreting) the args.

BrowserUK and others have provided a method to reach around the command shell and get what the user originally typed in.

Update: On second thought - it probably IS a good idea to use Getopt::Long after getting the args from the Windows Kernel.

[flyingmoose]

I would suggest you test for Windows ($^O=~/win/) and then reassemble the command line before letting your program muck with it.