Getting data from clipboard - c++

Question

I am trying to get data from clipboard but it doesn't seem to be displaying any data when i copy to my clipboard
Here is my clipboard class
namespace Diall_ClipBoard_catch
{
class ClipBoard
{
private:
::HANDLE dHDat;
::std::string tmpstringsign;
bool isopen;
char * dHbuffer;
char * dHbuffertemp;
char * dNtoken;
public:
ClipBoard(void)
{
this->dHbuffer = "";
this->dHbuffertemp = "";
this->tmpstringsign = "dnb_4554_2102";
this->isopen = false;
};
~ClipBoard(void)
{
if(this-isopen)
{
::CloseClipboard();
this->isopen = false;
}
}
void GetData(void)
{
this->Start();
if(this->isopen)
{
this->dHDat = ::GetClipboardData(CF_TEXT);
if(this->dHDat)
{
this->dHbuffer = (char*)::GlobalLock(this->dHDat);
if(::std::strcmp(this->dHbuffertemp, this->dHbuffer)!=0 && this->dHbuffer != "" && this->dHbuffer != NULL)
{
this->dHbuffertemp = this->dHbuffer;
::std::cout << this->dHbuffer << "\n";
}
::GlobalUnlock(this->dHDat);
}
this->~ClipBoard();
::Sleep(1000);
}
}
private:
Start(void)
{
}
} ;
}
And here is my main.cpp
#include <iostream>
#include <windows.h>
#include <cstring>
#include "Clipboard.h"
int main()
{
::Diall_ClipBoard_catch::ClipBoard * clipboard = new Diall_ClipBoard_catch::ClipBoard();
while(1)
{
clipboard->GetData();
}
return 0;
}
Even though I do not get any error when i build and run on Codeblocks, I still don't get any data displayed to my console.
Even though I have played around with the compiler settings on codeblock, I still haven't been able to get it to work

Answer 1

The comments have given enough information to fix this problem.
In the Start() function, you need some API calls, such as OpenClipboard, SetClipboardData.
And you did not set isopen to true, so when debugging, you will find that the breakpoint cannot reach GetClipboardData ().
Add the following code to test:
Start(void)
{
const char* output = "Hello World";
const size_t len = strlen(output) + 1;
HGLOBAL hMem = GlobalAlloc(GMEM_MOVEABLE, len);
memcpy(GlobalLock(hMem), output, len);
GlobalUnlock(hMem);
if (!OpenClipboard(NULL))
{
return;
}
EmptyClipboard();
SetClipboardData(CF_TEXT, hMem);
this->isopen = TRUE;
}
Note: The above code uses SetClipboardData to copy the text to the clipboard, and then uses GetClipboardData to get the text.
You can also use the clipboard to copy text yourself. Run the code and check whether the return value of the GetClipboardSequenceNumber function has changed. If it changes, it means that the clipboard contents have changed or the clipboard has been emptied.
Code Sample:
#include <iostream>
#include <windows.h>
#include <cstring>
namespace Diall_ClipBoard_catch
{
class ClipBoard
{
private:
::HANDLE dHDat;
::std::string tmpstringsign;
bool isopen;
char* dHbuffer;
char* dHbuffertemp;
char* dNtoken;
public:
ClipBoard(void)
{
this->dHbuffer = const_cast <char*>("");
this->dHbuffertemp = const_cast <char*>("");
this->tmpstringsign = "dnb_4554_2102";
this->isopen = false;
};
~ClipBoard(void)
{
}
void GetData(void)
{
this->Start();
if (this->isopen)
{
this->dHDat = ::GetClipboardData(CF_TEXT);
if (this->dHDat)
{
this->dHbuffer = (char*)::GlobalLock(this->dHDat);
if (::std::strcmp(this->dHbuffertemp, this->dHbuffer) != 0 && this->dHbuffer != "" && this->dHbuffer != NULL)
{
this->dHbuffertemp = this->dHbuffer;
::std::cout << this->dHbuffer << "\n";
}
::GlobalUnlock(this->dHDat);
}
EmptyClipboard();
CloseClipboard();
this->isopen = FALSE;
::Sleep(1000);
}
}
private:
void Start(void)
{
if (!OpenClipboard(NULL))
{
return;
}
this->isopen = TRUE;
}
};
}
int main()
{
::Diall_ClipBoard_catch::ClipBoard* clipboard = new Diall_ClipBoard_catch::ClipBoard();
int temp1 = 0, temp2 = 0;
EmptyClipboard();
while (1)
{
temp1 = GetClipboardSequenceNumber();
if (temp1!= temp2)
{
clipboard->GetData();
}
temp2 = temp1;
}
return 0;
}
Debug: