Convert WinApi type to Qt type
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Hi
This code is working fine, but in ending I got error (debug) "Exception at 0x5313a407, code: 0xc0000005: read access violation at: 0x0, flags=0x0"
@ HWND activeWindow;
activeWindow = GetForegroundWindow();
LPWSTR l_windowTitle;
SetWindowText(activeWindow,L"Hi!");
GetWindowText(activeWindow,l_windowTitle,256);
QString wchr = QString::fromWCharArray(l_windowTitle);
qDebug()<<wchr;@
Why? -
Edit code
@ HWND activeWindow;
activeWindow = GetForegroundWindow();
LPWSTR l_windowTitle = L"";
LPWSTR l_windowTitle2;
GetWindowText(activeWindow,l_windowTitle,256);
GetWindowText(activeWindow,l_windowTitle2,256);qDebug()<<QString::fromWCharArray(l_windowTitle); qDebug()<<QString::fromWCharArray(l_windowTitle2);@output without error
""
""
@ HWND activeWindow;
activeWindow = GetForegroundWindow();
LPWSTR l_windowTitle;
GetWindowText(activeWindow,l_windowTitle,256);qDebug()<<QString::fromWCharArray(l_windowTitle);@
output with error
"Title message" -
And now I am editing my code and this work perfectly. But why? ^_^
@ HWND activeWindow;
activeWindow = GetForegroundWindow();
char testVar[256];
GetWindowTextA(activeWindow,testVar,sizeof testVar);qDebug()<<testVar;@ -
How should it work if you didn't initialized your wchar_t variables?
LPWSTR is simple pointer in memory of wchar_t type:
@
// LPWSTR l_windowTitle is the same as
wchar_t * windowTitle;
@And after what you are trying to get 256 bytes to this uninitialized place in memory, of cause it will fail!
@
//
HWND activeWindow = GetForegroundWindow();
LPWSTR l_windowTitle = new wchar_t[256]; // or better use winapi memory initialization functions if you use wrappers for wchar_t type
GetWindowText(activeWindow,l_windowTitle,255);// let 1 byte for \0
qDebug()<<QString::fromWCharArray(l_windowTitle);
// free memory after you don't need it anymore
delete [] l_windowTitle;
@ -
Thanks ^_^
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Please add "[SOLVED]" prefix left to the subject topic. And have fun with coding!