So, I take it that even with properly declared types, Win32::API::Struct is a no go here as the native Wlan API uses enums all over the place, e.g. those DOT11 things?

There are no workarounds? I mean, in the call to the DLL, I cut corners by using ints.

Code doesn't run? OK, I had just typed the .pl in w/o testing it. Now, I just d/led script and module from the website and they don't throw errors here. My Struct.pm contains this header info:

######################################################################
+#
#
# Win32::API::Struct - Perl Win32 API struct Facility
# 
# Version: 0.45 
# Date: 28 Nov 2006
# Author: Aldo Calpini <dada@perl.it>
# Maintainer: Cosimo Streppone <cosimo@cpan.org>
#
# $Id: Struct.pm,v 1.0 2001/10/30 13:57:31 dada Exp $
######################################################################
+#
[download]

Your using a module 6 years older than the current version with .68-.45*100 releases in between. A 6 year old module isn't necessarily bad, but if it has had 2 dozen releases since in 6 years, using such an old version is ill advised. Try using the latest version of Win32::API.

As an experiment, I installed 0.45 of Win32::API, your code still doesn't run.

C:\Documents and Settings\Owner\Desktop\cpan libs\Win32-Wlan-0.06>perl
+ wlan.pl
The system cannot find the file specified at C:/perl512/site/lib/Win32
+/Wlan/API.
pm line 381, <DATA> line 164.

C:\Documents and Settings\Owner\Desktop\cpan libs\Win32-Wlan-0.06>perl
+ -MWin32::
API -MWin32::Wlan::API -e "print $Win32::API::VERSION"
0.45
C:\Documents and Settings\Owner\Desktop\cpan libs\Win32-Wlan-0.06>
[download]

Internally, Win32::API 0.45 still generates a garbage struct since your using undefined Win32::API types.

#from Win32::API::Struct 0.45
sub Pack {
    my $self = shift;
    my($packing, $items, $recipients) = $self->getPack();
    DEBUG "(PM)Struct::Pack: $self->{__typedef__}(buffer) = pack($pack
+ing, @$items)\n";
    $self->{buffer} = pack($packing, @$items);
    if(DEBUG) {
        for my $i (0..$self->sizeof-1) {
            printf "    %3d: 0x%02x\n", $i, ord(substr($self->{buffer}
+, $i, 1));
        }
    }
    $self->{buffer_recipients} = $recipients
}
[download]

$packing contains "SL". I modified Wlan::API's WlanConnect to

sub WlanConnect {
    croak "Wlan functions are not available" unless $wlan_available;
    my ($handle, $guuid, $profilename, $ssid) = @_;
    
    my $pDot11Ssid = Win32::API::Struct->new('DOT11_SSID');
    $pDot11Ssid->{uSSIDLength} = length $ssid;
    $pDot11Ssid->{ucSSID}      = $ssid;

    my $Wlan_connection_parameters = Win32::API::Struct->new('WLAN_CON
+NECTION_PARAMETERS');
    $Wlan_connection_parameters->{wlanConnectionMode} = 0;
    $Wlan_connection_parameters->{strProfile}         = $profilename;
    $Wlan_connection_parameters->{pDot11Ssid}         = $pDot11Ssid;
    $Wlan_connection_parameters->{pDesiredBssidList}  = 0;
    $Wlan_connection_parameters->{dot11BssType}       = 3;
    $Wlan_connection_parameters->{dwFlags}            = 0;

    my $reterr =  $API{ WlanConnect }->Call($handle, $guuid, $Wlan_con
+nection_parameters, 0);
    $reterr == 0 or die "WlanConnect return Error $reterr ";
};
[download]

and reran it under Win32::API, 0.45.

C:\Documents and Settings\Owner\Desktop\cpan libs\Win32-Wlan-0.06>perl
+ wlan.pl
WlanConnect return Error 87  at C:/perl512/site/lib/Win32/Wlan/API.pm 
+line 382,
<DATA> line 164.

C:\Documents and Settings\Owner\Desktop\cpan libs\Win32-Wlan-0.06>perl
+ -MWin32:
API -MWin32::Wlan::API -e "print $Win32::API::VERSION"
0.45
C:\Documents and Settings\Owner\Desktop\cpan libs\Win32-Wlan-0.06>
[download]

The work around is to use "INT" instead of enums specific types and keep a hash that converts enum slice names (as hash key names) to numeric equivalents (hash key value). Not all the things in WLAN_CONNECTION_PARAMETERS are enums. Some are pointers to other structs. Can I ask what level is your knowledge of C?

update, at first glance, there seems to be a bug in latest Win32::API, a ::Struct with a pointer to a ::Struct is broken, the parent ::Struct always treats the child ::Struct nested inline struct, not a struct pointer. So the Error 87 invalid parameter is the limit of using Win32::API::Struct module. You have to use pack, there probably is no alternative.

i got WlanConnect to work, here is your WlanConnect, it makes my wireless popup bubble come up, so it works

sub WlanConnect {
    croak "Wlan functions are not available" unless $wlan_available;
    my ($handle, $guuid, $profilename, $ssid) = @_;
    
    # possibly overkill, a pDot11Ssid = 0 should suffice
    #my $pDot11Ssid = Win32::API::Struct->new('PDOT11_SSID');
    #$pDot11Ssid->{uSSIDLength} = length $ssid;
    #$pDot11Ssid->{ucSSID}      = $ssid;

    my $SSIDstruct = pack('LZ[32]',length $ssid, $ssid ); #not overflo
+w checked
    my $Wlan_connection_parameters = pack('LPPJLL', 0, $profilename, $
+SSIDstruct, 0, 3, 0);

    #$Wlan_connection_parameters->{wlanConnectionMode} = 0;
    #$Wlan_connection_parameters->{strProfile}         = $profilename;
    #$Wlan_connection_parameters->{pDot11Ssid}         = $pDot11Ssid;
    #$Wlan_connection_parameters->{pDesiredBssidList}  = 0;
    #$Wlan_connection_parameters->{dot11BssType}       = 3;
    #$Wlan_connection_parameters->{dwFlags}            = 0;

    my $reterr =  $API{ WlanConnect }->Call($handle, $guuid, $Wlan_con
+nection_parameters, 0);
    $reterr == 0 or die "WlanConnect return Error $reterr ";
}
[download]

I also changed main for null safety and to work on my machine

sub main {
    $ARGV[0] = 'removed';
    $ARGV[1] = 'removed';
    die "USAGE: $0 PROFILENAME SSID\n" unless($ARGV[1]);
    my $profilename = $ARGV[0];
    my $ssid = $ARGV[1];

    my $wlan_handle = WlanOpenHandle();
    my @interfaces = WlanEnumInterfaces($wlan_handle);
    my $wlan_guuid = $interfaces[0]->{guuid};
    $profilename = encode('UTF-16LE', $profilename."\x00");
    WlanConnect($wlan_handle, $wlan_guuid, $profilename, $ssid);
}
[download]

I dont think my pack codes work on x64 BTW. Perhaps another monk can rewrite them to be portable, or you can just make another SOPW post.