How to copy string to clipboard in C?

Question

The SetClipboardData function requires a HANDLE reference; I'm having trouble converting my string for use in the function.

Here is my code:

char* output = "Test";
HLOCAL hMem =  LocalAlloc( LHND,1024);
char* cptr = (char*) LocalLock(hMem);
memcpy( cptr, output, 500 );
SetClipboardData(CF_TEXT, hMem);
LocalUnlock( hMem );
LocalFree( hMem );
CloseClipboard();

What am I doing wrong here and what's the proper way to do it?

Thanks.

Answer 1

Take a look at Microsoft's Documentation on using the clipboard. This requires that your using the WinAPI, but this shouldn't be a problem since your on Windows. Note that programming the Windows API is never simple unless you use a very high-level language.

Answer 2

Read the MSDN documentation for the SetClipboardData function. It appears you are missing a few steps and releasing the memory prematurely. First of all, you must call OpenClipboard before you can use SetClipboardData. Secondly, the system takes ownership of the memory passed to the clipboard and in must be unlocked. Also, the memory must be movable, which requires the GMEM_MOVEABLE flag as used with GlobalAlloc (instead of LocalAlloc).

const char* output = "Test";
const size_t len = strlen(output) + 1;
HGLOBAL hMem =  GloalAlloc(GMEM_MOVEABLE, len);
memcpy(GlobalLock(hMem), output, len);
GlobalUnlock(hMem);
OpenClipboard(0);
EmptyClipboard();
SetClipboardData(CF_TEXT, hMem);
CloseClipboard();

Answer 3

TCHAR text[128];
.....
VERIFY(::OpenClipboard(0));
VERIFY(::EmptyClipboard());

// Calculate number of bytes to be written (includes '\0' terminator)
const int nBytes = ( _tcslen(text) + 1 ) * sizeof(TCHAR);
// Allocate global memory
HGLOBAL hMem = ::GlobalAlloc(GMEM_MOVEABLE, nBytes);
// Get a pointer to the memory
LPVOID pMem = ::GlobalLock(hMem);

CopyMemory(pMem, text, nBytes);
GlobalUnlock(hMem);
SetClipboardData(CF_TEXT, hMem);      

VERIFY(::CloseClipboard());