Clipboard topic

[jj2007]

If the function succeeds, the return value is nonzero.
If the function fails, the return value is zero. To get extended error information, call GetLastError.

Closing the clipboard should never return zero, unless something has really gone bad. So the correct sequence should be

Code Select Expand

    .else                                       ; else
      invoke CloseClipboard                     ; close the clipboard
      .if !eax
           invoke GetLastError
           print str$(eax)
           print " error in CloseClipboard
      .endif
      jmp bye               ; eax = 0 or 1 now
    .endif

[hutch--]

Hi Leonard,

I confess its 13 years since I wrote that procedure but the only useful thing to return if data is available is the GlobalAlloc() memory handle. The .else block for CloseClipboard() is to close the clipboard if the opening call to OpenClipboard() did not fail. You are right that CloseClipboard() overwrites eax so it serves no purpose to zero it above the CloseClipboard() call.

If I was not working in Win 64 assembler, I would rewrite it as it needs to be done differently to make it more reliable.

It should test the return value of OpenClipboard() to ensure another app does not own the clipboard and if it is available and there is no data on the clipboard, it then should close the clipboard then return zero to indicate the the procedure was not able to get data from the clipboard.

[TimoVJL]

IsClipboardFormatAvailable is useful for that ?

[hutch--]

Microsoft seem to think so.