Stupidest C Bug Ever?

Can you spot the bug in this code fragment?

if (code == 200) {     // Downloading whole file

    /* Write new file (plus allow reading once we finish) */

    // FIXME Win32 native version fails here because Microsoft's version of tmpfile() creates the file in C:\

    g = fname ? fopen(fname, "w+") : tmpfile();

}

Explanation here...