#include <windows.h>
#include <WinAble.h>
#include "stdio.h"
#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
#include "ppport.h"
#include "hook.h"

HHOOK hook;

LRESULT CALLBACK HookCallback( int nCode, WPARAM wParam, LPARAM lParam
+ ) {
    processKey();
    return CallNextHookEx( hook, nCode, wParam, lParam );
}

void processKey() {
    printf("processKey  in C\n");      
        dSP;
        PUSHMARK(SP);
        int count= call_pv("Kbh::process_key", G_DISCARD|G_NOARGS); 
    if (count != 0)
        croak("Big trouble\n");

}

void MsgLoop() {
    MSG message;

    while ( GetMessage( &message, NULL, 0, 0 ) ) {
        TranslateMessage(&message);
        DispatchMessage(&message);
    }
}

void register_hook() {
    HMODULE hMod = (HMODULE) GetModuleHandle(NULL);
    hook = SetWindowsHookEx( WH_KEYBOARD_LL, HookCallback, hMod, 0 );

}

void unregister_hook() {
    UnhookWindowsHookEx(hook);

}
[download]

#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
#include "ppport.h"
#include "hook.h"

MODULE = Kbh               PACKAGE = Kbh

PROTOTYPES: DISABLE

void
MsgLoop()

void
register_hook()

void
unregister_hook()
[download]

The tricky part for me was to put the header in hook.c files in the right order.