Hi, rem45acp,

I suggest you use InlineX::C2XS to get the task done with out any annoyance. first: create a test.pl like below:

use strict;
use Inline C => Config =>
    LIBS => "-LE:/drivers/usb/devasys_i2cio -lusbi2cio",
    INC => "-IE:/drivers/usb/devasys_i2cio",
    BUILD_NOISY => 1;
use Inline C => q {
#include <windows.h>
#include "Usbi2cio.h"
#include <stdio.h>

void OpenDevice()
{
    HANDLE handle = INVALID_HANDLE_VALUE;
    
    handle = DAPI_OpenDeviceInstance("UsbI2cIo", 0);
    
    if (handle == INVALID_HANDLE_VALUE) {
        printf("Could not open device\n");
    }
    else {
        printf("Opened device!\n");
    }
}

};
[download]

then run: c2xs ....... it will produce a XS package for you. Please refer Inline::C2XS doc for details.