? "\0abc" : "\0xyz"

[D. J. Bernstein]

The following code produces incorrect results under gcc 2.8.1, incorrect
results under egcs 2.91.66, correct results under gcc 2.7.2.3, and
_presumably_ (see below) incorrect results under the latest gcc:

   doit(int flag)
   {
     printf(1 + (flag ? "\0wrong\n" : "\0right\n"));
   }
   main()
   {
     doit(0);
   }

I'm not familiar with the gcc internals, but after a minute of poking
around I found the fragment

      case STRING_CST:
        return (TREE_STRING_LENGTH (arg0) == TREE_STRING_LENGTH (arg1)
                && ! strncmp (TREE_STRING_POINTER (arg0),
                              TREE_STRING_POINTER (arg1),
                              TREE_STRING_LENGTH (arg0)));

in gcc.gnu.org/cgi-bin/cvsweb.cgi/~checkout~/egcs/gcc/fold-const.c.
Remember that, according to the C standard, a character string literal
is an array of bytes, not necessarily a string.

---Dan