Screenshot erstellen

Hallo Forenmitgleider
Ich komme mal gleich zur sache:

#include <windows.h>
#include <string>
#include <iostream>

using namespace std;

class CStellwerk
{
private:
    HWND m_hDesktop;
public:

    void MakeScreenshot(char SavePath[]);
    void SaveScreen(HWND pScreen, char Path[]);
};

void CStellwerk::MakeScreenshot(char SavePath[])
{
     m_hDesktop =  GetDesktopWindow();
     if(m_hDesktop == NULL)
     {
         exit(1);
     }
     SaveScreen(m_hDesktop,SavePath);
}

int main()
{
    CStellwerk Stellwerk;
    Stellwerk.MakeScreenshot("C:\\screen.bmp");

}

void CStellwerk::SaveScreen(HWND pScreen, char Path[])
{
int     nWidth  = GetSystemMetrics(SM_CXSCREEN);
int     nHeight = GetSystemMetrics(SM_CYSCREEN);

HWND    hWnd    = ::GetDesktopWindow();
HDC     hdc     = ::GetDC(hWnd);
HDC     memDC   = ::CreateCompatibleDC(hdc);
HBITMAP hbm     = ::CreateCompatibleBitmap(hdc, nWidth, nHeight);
HBITMAP hbmOld  = (HBITMAP)::SelectObject(memDC, hbm);

::BitBlt(memDC, 0, 0, nWidth, nHeight, hdc, 0, 0, SRCCOPY);

BITMAPINFO bmi;

ZeroMemory(&bmi, sizeof(bmi));

bmi.bmiHeader.biSize         = sizeof(BITMAPINFOHEADER);
bmi.bmiHeader.biWidth        = nWidth;
bmi.bmiHeader.biHeight       = nHeight;
bmi.bmiHeader.biBitCount     = 24;
bmi.bmiHeader.biPlanes       = 1;
bmi.bmiHeader.biCompression  = BI_RGB;
bmi.bmiHeader.biSizeImage = bmi.bmiHeader.biBitCount * nWidth * nHeight / 8;

BYTE *pbBits = new BYTE[bmi.bmiHeader.biSizeImage];

::GetDIBits( memDC,
             hbm,
             0,
             bmi.bmiHeader.biHeight,
             pbBits,
             &bmi,
             DIB_RGB_COLORS );

BITMAPFILEHEADER bfh;

bfh.bfType      = ('M' << 8) + 'B';
bfh.bfSize      = sizeof(BITMAPFILEHEADER)  +
                  bmi.bmiHeader.biSizeImage +
                  sizeof(BITMAPINFOHEADER);
bfh.bfReserved1 = 0;
bfh.bfReserved2 = 0;
bfh.bfOffBits   = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);
//
//  Hier:
//
HANDLE hfile = CreateFile( _T("c:\\screen.bmp"), // UM DIESE ZEILE GEHT ES!
                           GENERIC_WRITE,
                           0,
                           0,
                           OPEN_ALWAYS,
                           0,
                           0 );

DWORD dwWritten;

WriteFile(hfile,&bfh,           sizeof(bfh),               &dwWritten, NULL);
WriteFile(hfile,&bmi.bmiHeader, sizeof(BITMAPINFOHEADER),  &dwWritten, NULL);
WriteFile(hfile,pbBits,         bmi.bmiHeader.biSizeImage, &dwWritten, NULL);

CloseHandle(hfile);

::SelectObject(memDC, hbmOld);
::DeleteDC(memDC);
::ReleaseDC(hWnd,hdc);
::DeleteObject(hbm);

delete[] pbBits;
}

Ergibt beim C::B folgende Fehler bei mir:

main.cpp: In member function void CStellwerk::SaveScreen(HWND__*, char*)': main.cpp:81: error:_T' was not declared in this scope
main.cpp:81: warning: unused variable '_T'
Process terminated with status 1 (0 minutes, 0 seconds)
1 errors, 1 warnings

Nimm statt _T einfach TEXT(), das funktionier häufiger.
Oder gib am anfang der datei #define _T TEXT an.

Also jetzt rastet der Compiler richtig.
Das doofe bei solchen Fehlern ist, dass ich nichtmal erahnen kann was los ist.

Linking console executable: bin\Debug\screeny.exe
obj\Debug\main.o: In function ZN10CStellwerk10SaveScreenEP6HWND(char *)': main.cpp:45: undefined reference toCreateCompatibleDC@4'
main.cpp:46: undefined reference to CreateCompatibleBitmap@12' main.cpp:47: undefined reference toSelectObject@8'
main.cpp:49: undefined reference to BitBlt@36' main.cpp:65: undefined reference toGetDIBits@28'
main.cpp:99: undefined reference to SelectObject@8' main.cpp:100: undefined reference toDeleteDC@4'
main.cpp:102: undefined reference to `DeleteObject@4'
collect2: ld returned 1 exit status

Bibliothek Gdi32.lib inkludieren !

Das wars, danke