How to get string from pointer - winapi

Question

GetWindowThreadProcessId(hwndFoundWindow, &dwTrayProcessID);
HANDLE hTrayProc = OpenProcess(PROCESS_ALL_ACCESS, 0, dwTrayProcessID);
int iButtonsCount = SendMessage(hwndFoundWindow, TB_BUTTONCOUNT, 0, 0);
LPVOID lpData = VirtualAllocEx(hTrayProc, NULL, sizeof(TBBUTTON), MEM_COMMIT, PAGE_READWRITE);
int iButton;
DWORD dwBytesRead;
TBBUTTON buttonData;
dwBytesRead = -1;
int chk_data = (int)SendMessage(hwndFoundWindow, TB_GETBUTTON, iButton, (LPARAM)lpData);
ReadProcessMemory(hTrayProc, lpData, &buttonData, sizeof(TBBUTTON), &dwBytesRead);
int len_text = (int)SendMessage(hwndFoundWindow, TB_GETBUTTONTEXTW, buttonData.idCommand, (LPARAM)lpData);
till now, i know the length of button's text but i also need to get the text to display on console.
my problem is i do not really know how to get that text from the button. please kindly help.
what i am trying is ... trying to access to lpData to get the string inside, but could not do that.

Answer 1

My first comment is that you need to add error checking to your code. As far as I can see, you perform no checking of return values. Any of the API functions you call could fail. If you don't check return values for errors then you have no way of diagnosing where you went wrong.
For instance, starting with GetWindowThreadProcessId, you need to write it like this:
if (GetWindowThreadProcessId(hwndFoundWindow, &dwTrayProcessID) == 0)
{
// handle error
}
And so on for all the other functions. Consult MSDN carefully to understand how each function signals failure.
Now to the main part of the question. I believe that it is the TB_GETBUTTONTEXTW message that is giving you trouble. You need to write it like this:
LRESULT len = SendMessage(hwndFoundWindow, TB_GETBUTTONTEXTW,
buttonData.idCommand, NULL);
if (len == -1)
{
// handle error
}
size_t size = sizeof(wchar_t)*(len+1);
LPVOID lpData = VirtualAllocEx(hTrayProc, NULL, size, MEM_COMMIT, PAGE_READWRITE);
if (lpData == NULL)
{
// handle error
}
len = SendMessage(hwndFoundWindow, TB_GETBUTTONTEXTW,
buttonData.idCommand, (LPARAM)lpData);
if (len == -1)
{
// handle error
}
wchar_t* str = new wchar_t[len+1];
if (!ReadProcessMemory(hTrayProc, lpData, (LPVOID)str, size, NULL))
{
// handle error
}
// the text is now in str, as a null-terminated UTF-16 string
delete[] str;

Answer 2

You need this: (see documentation of TB_GETBUTTONTEXTW).
WCHAR *buffer ;
int len_text = (int)SendMessage(hwndFoundWindow, TB_GETBUTTONTEXTW,
buttonData.idCommand, (LPARAM)NULL);
buffer = (WCHAR*)malloc(sizeof(WCHAR) * (len_text + 1)) ;
SendMessage(hwndFoundWindow, TB_GETBUTTONTEXTW,
buttonData.idCommand, (LPARAM)buffer);
....
free(buffer) ;