A Java long is not necessarily a scalar type in C
--------------------------------------------
Not all C compilers support native 64-bit integers.
They may have to use a structure:
e.g.
int64_t x;
This means that casting a Java long to a pointer for
example inside some C code may not succeed.
E.g.
>From src/win32/javavm/runtime/jvmdi_md.c:
      case SUSPENDED: {
        struct javaframe *currFrame;
        ExecEnv* thread_ee = (ExecEnv *)unhand(h)->eetop;
        if ((thread_ee != 0) &&
            ((currFrame = thread_ee->current_frame) != 0) &&
            (currFrame->lastpc != 0) &&
>From /src/share/jvm/runtime/debug.c
static void
threadDumpInfoLocked(TID tid, bool_t verbose)
{
    int priority;
    jio_fprintf(stderr, " %s",
                Object2CString((JHandle *) THREAD(tid)->name));
    if (verbose == TRUE) {
        ExecEnv *ee = (ExecEnv *)THREAD(tid)->eetop;
        sys_thread_t *t = ee ? EE2SysThread(ee) : 0;


But eetop is declared a Java long, so is an int64_t, which can be a structure,
so
can not be cast to a pointer.

Perhaps accessing a pointer in this fashion should be isolated in a macro.
I am not sure when happens on an AS/400 which uses 16 byte pointers.

The code should at least use ll2ptr and ptr2ll macros.