couldn't find function symbol in library

Question

Declaring SCardStatus function causes the error: "couldn't find function symbol in library"

The Code is as follows:

Cu.import('resource://gre/modules/ctypes.jsm');
var is64bit = ctypes.voidptr_t.size == 4 ? false : true;
var ifdef_UNICODE = true;
var TYPES = {
    ABI: is64bit ? ctypes.default_abi : ctypes.winapi_abi,
    CHAR: ctypes.char,
    DWORD: ctypes.uint32_t,
    LONG: ctypes.long,
    LPCVOID: ctypes.voidptr_t,
    ULONG_PTR: is64bit ? ctypes.uint64_t : ctypes.unsigned_long,
    WCHAR: ctypes.jschar,
};
TYPES.LPSTR = TYPES.CHAR.ptr;
TYPES.LPDWORD = TYPES.DWORD.ptr;
TYPES.LPWSTR = TYPES.WCHAR.ptr;
TYPES.SCARDHANDLE = TYPES.ULONG_PTR;
TYPES.LPBYTE = TYPES.LPSTR;
TYPES.LPTSTR = ifdef_UNICODE ? TYPES.LPWSTR : TYPES.LPSTR;
var cardLib = ctypes.open('Winscard');
var SCardStatus = cardLib.declare('SCardStatus', TYPES.ABI, TYPES.LONG, TYPES.SCARDHANDLE, TYPES.LPTSTR, TYPES.LPDWORD, TYPES.LPDWORD, TYPES.LPDWORD, TYPES.LPBYTE, TYPES.LPDWORD );

I guess that TYPES.LPBYTE is not correct, according to https://msdn.microsoft.com/en-us/library/windows/desktop/aa379803%28v=vs.85%29.aspx , LPBYTE should be a Pointer to a 32-byte buffer that receives the ATR string from the currently inserted card, if available. However I could not fix it, I appreciate any helps in advanced.

Answer 1

In winapi if the functions have two versions, unicode version and ascii verison IF it takes strings. So the docs show this accepts characters, so on the page it shows: SCardStatusW (Unicode) and SCardStatusA (ANSI) so you have to define it like this: var SCardStatus = cardLib.declare(ifdef_UNICODE ? 'SCardStatusW' : 'SCardStatusA', ....