#define MAKELANGID(p, s)       ((((WORD  )(s)) << 10) | (WORD  )(p))

#define PRIMARYLANGID(lgid)    ((WORD  )(lgid) & 0x3ff)
#define SUBLANGID(lgid)        ((WORD  )(lgid) >> 10)

#define MAKEINTRESOURCEA(i) ((LPSTR)((ULONG_PTR)((WORD)(i))))
#define MAKEINTRESOURCE  MAKEINTRESOURCEA

#define MB_USERICON                 0x00000080L

typedef unsigned long ULONG_PTR;
typedef ULONG_PTR DWORD_PTR;


typedef void* MSGBOXCALLBACK;


typedef struct _MSGBOXPARAMS{
    UINT            cbSize;
    HWND            hwndOwner;
    HINSTANCE       hInstance;
    LPCSTR          lpszText;
    LPCSTR          lpszCaption;
    DWORD           dwStyle;
    LPCSTR          lpszIcon;
    DWORD_PTR       dwContextHelpId;
    MSGBOXCALLBACK  lpfnMsgBoxCallback;
    DWORD           dwLanguageId;
}MSGBOXPARAMS;

/* 
   ...below is the id of the icon within the acknex.exe. its the only 
      way (and icon) you can display as a user defined icon unless you 
      build it yourself or do the resource hack they explain in the manual.

      EDIT: 

      if you have an icon resource in a dll (see next post down)
                                                                              */
#define IDI_ICON       103  

 
MSGBOXPARAMS mbp;

int _MessageBox(HWND hwndOwner, LPCSTR lpszText, LPCSTR lpszCaption, DWORD dwStyle, UINT lpszIcon)
{
      mbp.cbSize = sizeof(MSGBOXPARAMS);
      mbp.hwndOwner = hwndOwner; 
      mbp.hInstance = GetModuleHandle(NULL); 
      mbp.lpszText = lpszText;
      mbp.lpszCaption = lpszCaption;
      mbp.dwStyle = dwStyle | MB_USERICON; 
     
      mbp.lpszIcon = MAKEINTRESOURCE(lpszIcon); 

      mbp.dwContextHelpId = 0; 
      mbp.lpfnMsgBoxCallback = NULL; 
      mbp.dwLanguageId = MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT);
    
return MessageBoxIndirect(&mbp);
} 

 _MessageBox(NULL,"MessageBox Hooks, Callbacks, User Defined Buttons & Icons", "Lite-C", MB_OK, IDI_ICON);