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c++stringwinapitchar

TCHAR[], LPWSTR, LPTSTR and GetWindow Text function

So the GetWindowText is declared on MSDN as follows:

int GetWindowText(      
    HWND hWnd,
    LPTSTR lpString,
    int nMaxCount
);

However for the code to work we have to declare the second parameter as

TCHAR[255] WTitle;

and then call the function GetWindowText(hWnd,Wtitle,255); The LPTSTR is a pointer to an array of tchar, so declaring LPTSTR is similar to declaring TCHAR[]? It doesn't work this way though. When using TCHAR[] the program returns valid GetWindowText result (it is an integer equal to the number of symbols in the title). The question is : how can I get the exact title out of TCHAR[] ? Code like 

TCHAR[255] WTitle;
cout<< WTitle;

or

cout<< *Wtitle;

returns numbers. How can I compare this with a given string?

TCHAR[4] Test= __T("TEST")
if (WTitle == Test) do smth

doesn't work also.

Solution

  • OK, a few definitions first.

    The 'T' types are definitions that will evaluate to either CHAR (single byte) or WCHAR (double-byte), depending upon whether you've got the _UNICODE symbol defined in your build settings. The intent is to let you target both ANSI and UNICODE with a single set of source code.

    The definitions:

    TCHAR title[100];
TCHAR * pszTitle;

    ...are not equivalent. The first defines a buffer of 100 TCHARs. The second defines a pointer to one or more TCHARs, but doesn't point it at a buffer. Further,

    sizeof(title) == 100   (or 200, if _UNICODE symbol is defined)
sizeof(pszTitle) == 4  (size of a pointer in Win32)

    If you have a function like this:

    void foo(LPCTSTR str);

    ...you can pass either of the above two variables in:

    foo(title);    // passes in the address of title[0]
foo(pszTitle); // passes in a copy of the pointer value

    OK, so the reason you're getting numbers is probably because you do have UNICODE defined (so characters are wide), and you're using cout, which is specific to single-byte characters. Use wcout instead:

    wcout << title;

    Finally, these won't work:

    TCHAR[4] Test == __T("TEST")   ("==" is equality comparison, not assignment)
if (WTitle == Test) do smth    (you're comparing pointers, use wcscmp or similar)