How can I assign clipboard text to a variable in c++?

Question

I've written a program that highlights numbers and copies them. I would like to be able to do some basic math with the copied text, such as multiplication or addition, but I can't figure out how to assign the clipboard data to a variable. Basically, I would like to be able to copy a number, assign it to variable "a", then repeat with variable "b" and multiply the two together. I have figured out how to select and copy the number so that part isn't an issue. Any help would be appreciated, even a completely different approach than what I have tried.

Here is my latest attempt at the problem:

    HANDLE clip0;
    OpenClipboard(NULL);
    EmptyClipboard();
        clip0 = GetClipboardData(CF_TEXT);
     variable = (char)clip0;
    CloseClipboard();

where "variable" is the variable.

Whenever I run the program and tell it to output "variable", it returns the value of 0.

another attempt I made was this:

HANDLE clip1;
    if (OpenClipboard(NULL)) 
        clip1 = GetClipboardData(CF_TEXT);
     variable = (char)clip1;
    CloseClipboard();

but "variable" would always take on the value of -8

Answer 1

The text content of the clipboard is a c-string pointed to by c.

if(OpenClipboard(NULL) != FALSE)
{
  HANDLE clip0 = GetClipboardData(CF_TEXT); 
  if(clip0 != NULL)
  {
    char *c = reinterpret_cast<char*>(GlobalLock(clip0));
    // Use c before it goes out of scope
    ...
    GlobalUnlock(clip0);
  }
  CloseClipboard();
}

Answer 2

You need to call GlobalLock(clip0) to get a pointer to the data, rather than casting the handle. Then, when you're done, call GlobalUnlock to release the pointer.

OpenClipboard(NULL);
HANDLE clip0 = GetClipboardData(CF_TEXT);
char* p=(char*)GlobalLock(clip0);
variable=*p;
GlobalUnlock(clip0);
CloseClipboard();