[naviserver-devel] strict aliasing?

[Zoran V. <zv...@ar...>]

Hi

When you compile w/o debugging (i.e. with optimisation)
the GCC spits whole-lotta stuff like that:

tclthread.c:401: warning: dereferencing type-punned pointer will  
break strict-aliasing rules
tclthread.c:401: warning: dereferencing type-punned pointer will  
break strict-aliasing rules

The warning sems to trigger when a pointer is casted like this:

     enum {
         EAbsWaitIdx, EBroadcastIdx, ECreateIdx, EDestroyIdx, ESetIdx,
         ESignalIdx, ETimedWaitIdx, EWaitIdx
     } opt;

     if (!GetArgs(interp, objc, objv, opts, 'e', ECreateIdx,
                   (int *) &opt, (void **) &condPtr)) {
         return TCL_ERROR;

The "opt" and "condPtr" in GetArgs() are casted and it barks
at them. I cannot possibly imagine changing all code to
something like:

     enum {
         EAbsWaitIdx, EBroadcastIdx, ECreateIdx, EDestroyIdx, ESetIdx,
         ESignalIdx, ETimedWaitIdx, EWaitIdx
     } opt;
     int myOpt = (int)opt;

     if (!GetArgs(interp, objc, objv, opts, 'e', ECreateIdx,
                   &myOpt, (void **) &condPtr)) {
         return TCL_ERROR;

This would mean lots of work and may introduce errors.

I've read that you can use (starting with gcc 3.3) -fno-strict-aliasing
which would remove those warnings. But also, somebody said that the
effect of the "-O2" is gone in such cases (haven't be able to verify)

What to do?
Any ideas?

Zoran