Win32::API->Import($S{DLL_path}, 'int RegisterClient2(int *pnClientId, char *pszIPAddress)');

...

my $result = RegisterClient2($client_id, $S{read_IP});

##</code><code>##

my $RegisterClient2 = Win32::API->new($S{DLL_path}, 'int RegisterClient2(int *pnClientId, char *pszIPAddress)');

...

my $result = $RegisterClient2->Call($client_id, $S{read_IP});

##</code><code>##

use strict;
use warnings;
use Inline C => Config => MYEXTLIB => 'd:\path\to\CrappyLibrary.dll',
#use Inline C => Config => LIBS =>'-Ld:/path/to -lCrappyLibrary',
                          INC => '-Id:\path\to',BUILD_NOISY => 1;
use Inline C => 'DATA';

my $result = RegisterClient2($client_id, $S{read_IP});

__DATA__
__C__
#include "Easy4ApiDef.h"

##</code><code>##

Set up gcc environment - 3.4.5 (mingw-vista special r3)
Use of inherited AUTOLOAD for non-method main::RegisterClient2() is deprecated at inline.pl line 115.
Can't locate auto/main/RegisterCli.al in @INC (@INC contains: D:\meres\SAR\_Inline\lib C:/Perl/site/lib C:/Perl/lib .) at inline.pl line 115

##</code><code>##

extern "C" __declspec(dllexport) int RegisterClient2(int *pnClientId, const char *pszIPAddress);