returning c string pointer to gforth

My apologies in advance if this turns out to be a C programming question 
rather than a Gforth one: I'm a newbie to C (though not to Forth).

I'm trying to return a pointer to a string from a C function so I can 
use the string in Forth.

My string pointer ( in my latest attempt) is declared as a global variable:

  static char *text;

The function that sets the pointer is declared thus:

  const char* XPaste( )

and the code that sets the pointer is:

  text=malloc(size+1);
  memcpy(text,data,size +1);
  return text;

the function is defined in Forth as:

   c-function xpaste XPaste  -- a

My problem is that the address returned causes an "Invalid memory 
address" error when I try to access it. Where am I going wrong?

Thanks in advance,
Garry